Printing system, method of generating halftone processing rule, image processing device, and program acquiring parameters related to characteristic errors of the printing system

ABSTRACT

There are provided a printing system, a method of generating a halftone processing rule, a method of acquiring a characteristic parameter, image processing device and method, a halftone processing rule, a halftone image, a method of manufacturing a printed material, an ink jet printing system, and a program which are capable of reducing an operation load of a user and acquiring a halftone processing rule appropriate for the printing system. A characteristic parameter acquisition chart (100) including a pattern for acquiring characteristic parameters related to characteristics of the printing system is output, and the output characteristic parameter acquisition chart (100) is read by image reading means. The characteristic parameters are acquired by analyzing the read image of the characteristic parameter acquisition chart (100), and halftone processing rules that define the processing contents of halftone processes used in the printing system are generated based on the acquired characteristic parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 15/276,383, filed on Sep. 26, 2016, which is a “bypass”Continuation of PCT International Application No. PCT/JP2015/059348filed on Mar. 26, 2015 claiming priority to Japanese Patent ApplicationNo. 2014-066008 filed on Mar. 27, 2014, Japanese Patent Application No.2014-200066 filed on Sep. 30, 2014, Japanese Patent Application No.2014-200068 filed on Sep. 30, 2014, Japanese Patent Application No.2015-036460 filed on Feb. 26, 2015, Japanese Patent Application No.2015-036461 filed on Feb. 26, 2015, Japanese Patent Application No.2015-036462 filed on Feb. 26, 2015, Japanese Patent Application No.2015-036463 filed on Feb. 26, 2015, Japanese Patent Application No.2015-036464 filed on Feb. 26, 2015 and Japanese Patent Application No.2015-036465 filed on Feb. 26, 2015. Each of the above applications ishereby expressly incorporated by reference, in their entirety, into thepresent application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a printing system, a method ofgenerating a halftone processing rule, a method of acquiring acharacteristic parameter, image processing device and method, a halftoneprocessing rule, a halftone image, a printed material manufacturingmethod, an inkjet printing system, and a program, and more particularly,to an image processing technology of generating a print halftone imagefrom a continuous-tone image.

2. Description of the Related Art

In a printing system in which a printing device such as an ink jetprinting device or an offset printing device forms an image, a halftoneprocess is performed on data of a continuous-tone image expressed bymultiple gradations, and thus, data of a halftone image corresponding toan image output mode of the printing device is generated. The data ofthe halftone image is used as printing dot image data indicating a dotpattern in which dot arrangement of halftone dots reproduced by theprinting device or a size of each dot is defined. The printing deviceforms an image based on the data of the halftone image.

As the method of the halftone process, there are various methods such asa dither method, an error diffusion method, and a direct binary search(DBS) method. For example, in the dither method, multi-value data of thecontinuous-tone image is converted into binary dot data by comparing athreshold value and a pixel value of a processing target pixel using athreshold value matrix called a dither mask, assigning dot-ON pixels ina case where the pixel value is equal to or greater than the thresholdvalue and assigning dot-OFF pixels in a case where the pixel value isless than the threshold value.

JP2012-222433A describes a printing system capable of selecting ahalftone process appropriate for a printed material in consideration ofproductivity of the printed material. The printing system described inJP2012-222433A may select one signal processing condition from signalprocessing conditions of a plurality of halftone processes havingdifferent dot distribution characteristics, and may perform the halftoneprocess using the selected signal processing condition.

In the printing system described in JP2012-222433A, four printing modemay be prepared, and an operator may select the printing mode. If theprinting mode is selected, since a recommended halftone processingcondition is presented, the operator can select an optimum halftoneprocessing condition.

“Digital Halftoning Techniques for Printing” (Thrasvoulos N. PapasIS&T's 47Th Annual Conference, Rochester, N.Y., May 15-20, 1994),“Model-Based Digital Halftoning” (Thrasvoulos N. Papas, Jan P. Allebach,and David L. Neuhoff, IEEE SIGNAL PROCESSING MAGAZINE JULY 2003, p14-27), and “Inkjet Printer Model-Based Halftoning” (Je-Ho Lee and JanP. Allebach, IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 14. NO. 5 MAY2005, P 674-689) describe a technology called model-based halftoning.“Digital Halftoning Techniques for Printing” (Thrasvoulos N. PapasIS&T's 47Th Annual Conference, Rochester, N.Y., May 15-20, 1994),describes a method of performing halftone design capable of improvingdispersibility of a dot having an intermediate gradation based on animage in which the overlapping of dots is reproduced in consideration ofthe spreading of a dot and the size of a dot at the time of printingfrom the characteristics of the printing system. The term of “halftonedesign” means that the specific content of the halftone process isdesigned, that is, the halftone processing rule is generated.

“Model-Based Digital Halftoning” (Thrasvoulos N. Papas, Jan P. Allebach,and David L. Neuhoff, IEEE SIGNAL PROCESSING MAGAZINE JULY 2003, p14-27), and “Inkjet Printer Model-Based Halftoning” (Je-Ho Lee and JanP. Allebach, IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 14. NO. 5 May2005, P 674-689) describe a method of performing halftone design basedon an image in which bidirectional error characteristics as positionshift characteristics which is a position shift of a dot in an outwardpath and an inward path through a reciprocating operation in serialscanning are reproduced in addition to taking account of the overlappingof the dots.

JP2013-038643A describes a method of performing halftone design havingtolerance to a paper transport error or bidirectional error in a serialscanning type. JP2009-018479A describes a method of performing halftonedesign having tolerance to a position shift of a printing head in a lineprinter including a line head configured such that a plurality ofprinting head is arranged.

JP2013-038643A describes a multipath and JP2009-018479A describes asingle path, and these literatures describe that the halftone designcapable of improving the dispersibility of a dot on a per path basis isperformed. These literatures may be classified as a “path dispersionhalftoning” technology.

SUMMARY OF THE INVENTION

A printing result based on the halftone image generated through thehalftone process depends on the characteristics of the printing system.Accordingly, it is preferable that the halftone processing ruleappropriate for the printing system is generated based on thecharacteristic parameters related to the characteristics of the printingsystem.

For example, in an ink jet printing system, as the characteristicparameters related to the characteristics of the printing system, thereare resolution, the number of nozzles, ink kind, an average dot density,an average dot diameter, an average dot shape, a dot density, a dotdiameter, a dot shape, a dot forming position shift, non-jetting andlanding interference of each printing element. Among the above-describedvarious characteristic parameters, since the parameter of the dotdensity, the dot diameter, the dot shape or the landing interference ofeach printing element are changed depending on a combination of an inkor a printing medium to be used and the characteristics of a recordinghead and the dot forming position shift or the non-jetting is changed bythe state of the recording head, if the user inputs an appropriate valuefor the various parameters, an operation load is excessive. Thecharacteristics of the recording head include a frequency or a waveformof a driving signal applied to the recording head when an ink is jetted.For example, the state of the recording head indicates the inclining orbending of the recording head, a distance from the printing medium, or astate of each printing element.

The invention has been made in view of such circumstances, and it is anobject of the invention to provide a printing system, a method ofgenerating a halftone processing rule, an image processing device and aprogram which are capable of setting characteristic parameters relatedto characteristics of the printing system without giving an excessiveload to a user and capable of acquiring a halftone processing ruleappropriate for the printing system.

In the printing system described in JP2012-222433A, the user cancomprehend the halftone processing condition in which a total evaluationvalue is maximized for each printing mode, but the halftone processingcondition in which the total evaluation value is maximized is notnecessarily a condition in which the characteristics of the printingsystem in each printing mode are appropriately reflected.

That is, in the printing system capable of selecting the printing mode,it is preferable that the halftone process is performed using thehalftone processing rule appropriate for each printing mode. In order togenerate the halftone processing rule appropriate for each printingmode, it is preferable that the characteristics of the printing systemfor each printing mode are appropriately comprehended. The term of thehalftone processing condition corresponds to the term of a candidateprocessing condition described in Cited Literature 1.

The invention has been made in view of such circumstances, and it isanother object of the invention to provide a printing system, a methodof acquiring a characteristic parameter, an image processing device anda program which are capable of appropriately comprehendingcharacteristics of the printing system for each printing mode.

Other Problems

The model-based halftoning technology described in “Model-Based DigitalHalftoning” (Thrasvoulos N. Papas, Jan P. Allebach, and David L.Neuhoff, IEEE SIGNAL PROCESSING MAGAZINE JULY 2003, p 14-27) and “InkjetPrinter Model-Based Halftoning” (Je-Ho Lee and Jan P. Allebach, IEEETRANSACTIONS ON IMAGE PROCESSING, VOL. 14. NO. 5 MAY 2005, P 674-689)realizes the halftone process capable of achieving favorable imagequality even in a state in which there is the bidirectional error byreproducing the bidirectional error characteristics and generating theoptimum halftone processing rule in the serial scan type.

The path dispersion halftoning technology described in JP2013-038643Aand JP2009-018479A generates the halftone processing rule havingtolerance to the position shift error of the recording head, thebidirectional error or the paper transport error.

The system error taken into consideration in JP2013-038643A andJP2009-018479A is the position shift error of the recording head, thebidirectional error or the paper transport error, but a system errorother than these errors is added at the time of actual printing in somecases. For example, as an item of the system error which is not takeninto consideration in JP2013-038643A and JP2009-018479A, there is a headvibration error according to carriage movement, an error for eachnozzle, non-jetting, or an error for each droplet kind. The term of“printing head” corresponds to the term of “recording head”.

The path dispersion halftoning technology described in JP2013-038643A isa method of improving the dispersibility of each dot arrangement of eachscanning path, and the weighting of an evaluation value of thedispersibility of the entire image is in charge of the user.

In the method described in JP2013-038643A, there is a problem that anactual system error is not sufficiently reflected and thus, it isdifficult to necessarily perform the optimum halftone process in theactual system. For example, the halftone design using the related methodis performed in an excess restriction condition in a system in which thebidirectional error is completely none or a system in which thebidirectional error is extremely less, and image quality is deterioratedin some cases.

In the path dispersion halftoning technology described inJP2009-018479A, the halftone design having tolerance to only anattachment position error of a connection portion between the respectiveprinting heads is performed in the single path type.

However, as described above, since various system errors are added inaddition to the position error between the printing head at the time ofactual printing, in a case where the system is in a state in which thereis the system error other than the position error between the printingheads, favorable image quality is not acquired.

The invention has been made in view of such circumstances, and it isanother object of the invention to provide image processing device andmethod, a printing system, a method of generating a halftone processingrule, a halftone processing rule, a halftone image, a method ofmanufacturing a printed matter, and a program which are capable ofrealizing an appropriate halftone process capable of acquiring favorableimage quality in consideration of a system error influencing actualprinting.

In the ink jet printing device, when dots of ink droplets are jettedadjacent to each other on a recording medium, landing interferenceoccurs between the adjacent dots overlapping each other on the printingmedium in some cases. The landing interference indicates a phenomenon inwhich ink droplets adjacent to each other on the recording medium aredrawn to each other by the influence of surface energy of a liquid, andthus, the ink droplets are moved on the recording medium. Since the dotsare formed in positions shifted from the original landing positions dueto the landing interference, the granularity of the image isdeteriorated or gloss is not uniform, and thus, the image quality isdeteriorated.

The invention has been made in view of such circumstances, and it isanother object of the invention to provide image processing device andmethod, an ink jet printing system, and a program which are capable ofsuppressing image quality deterioration caused by landing interferenceand are capable of realizing the generation of the halftone imagecapable of forming an image having high image quality.

In order to achieve the aforementioned objects, the following inventionaspects are provided.

A printing system according to a first aspect is a printing systemcomprising: characteristic-parameter-acquisition-chart output means foroutputting a characteristic parameter acquisition chart including apattern for acquiring characteristic parameters related tocharacteristics of a printing system; image reading means for readingthe characteristic parameter acquisition chart output by thecharacteristic-parameter-acquisition-chart output means; characteristicparameter acquisition means for acquiring the characteristic parametersby analyzing a read image of the characteristic parameter acquisitionchart acquired by the image reading means; and halftone processgeneration means for generating halftone processing rules that definethe processing contents of halftone processes used in the printingsystem based on the characteristic parameter acquired by thecharacteristic parameter acquisition means.

According to the first aspect, the characteristic parameter acquisitionchart is output by the printing system, and the output characteristicparameter acquisition chart is read by the image reading means. Theinformation of the characteristic parameter is acquired from the readimage of the characteristic parameter acquisition chart, and thehalftone processing rule appropriate for the printing system isgenerated based on the acquired characteristic parameter.

According to the first aspect, it is possible to simply set thecharacteristic parameter of the printing system without giving anexcessive load to a user, and it is possible to generate the halftoneprocessing rule appropriate for the characteristics of the printingsystem.

As a second aspect, in the printing system according to the firstaspect, the halftone processing rule may be specified by a combinationof a halftone algorithm and a halftone parameter.

As a third aspect, in the printing system according to the secondaspect, any one method of a dither method, an error diffusion method,and a direct binary search method may be adopted as the halftonealgorithm.

As a fourth aspect, in the printing system according to the secondaspect or the third aspect, the halftone parameter may include at leastone parameter of a size and a threshold value of a dither mask in thedither method, a size of an error diffusion matrix, a diffusioncoefficient and setting of an applied gradation section of the errordiffusion matrix in the error diffusion method, the number of timespixels are updated and an exchange pixel range in the direct binarysearch method, or a parameter for evaluating system error tolerance.

As a fifth aspect, in the printing system according to any one of thefirst aspect to the fourth aspect, the printing system may include animage forming unit that includes a plurality of printing elementsserving to form dots on a printing medium, and the characteristics ofthe printing system may be characteristics that include at least one ofindividual recording characteristics of the plurality of printingelements or common characteristics to the plurality of printingelements.

As a sixth aspect, in the printing system according to the fifth aspect,the recording characteristics may be characteristics that include atleast one of a dot density, a dot diameter, a dot shape, a dot recordingposition error, or recording inexecutable abnormality.

As a seventh aspect, in the printing system according to the fifthaspect or the sixth aspect, the common characteristics may becharacteristics that include at least one of an average dot density, anaverage dot diameter, an average dot shape, or landing interference.

As an eighth aspect, in the printing system according to any one of thefifth aspect to the seventh aspect, the characteristic parameteracquisition means may acquire parameters related to the individualrecording characteristics of the printing element and the commoncharacteristics to the plurality of printing elements from the readimage of the characteristic parameter acquisition chart on whichrecording is performed multiple times by using the same printing elementby the characteristic-parameter-acquisition-chart output means.

As a ninth aspect, in the printing system according to any one of thefifth aspect to the eighth aspect, the characteristic parameteracquisition means may acquire parameters related to errors of theprinting system from the read image of the characteristic parameteracquisition chart on which recording is performed multiple times byusing the same printing element by thecharacteristic-parameter-acquisition-chart output means.

As a tenth aspect, in the printing system according to any one of thefifth aspect to the ninth aspect, the characteristic parameteracquisition chart may include a continuous dot pattern in which two ormore dots are recorded so as to be in contact, and the characteristicparameter acquisition means may acquire a parameter related to thelanding interference from the continuous dot pattern.

As an eleventh aspect, in the printing system according to the tenthaspect, the characteristic parameter acquisition chart may includemultiple kinds of continuous dot patterns in which at least any one ofan inter-dot distance between the two or more dots or a recording timedifference between the two or more dots is differentiated.

As a twelfth aspect, in the printing system according to any one of thefifth aspect to the eleventh aspect, the characteristic parameteracquisition chart may include a discrete dot pattern in which dots arediscretely recorded in an isolation state in which a single dot isisolated from another dot, and the characteristic parameter acquisitionmeans may generate dispersion information related to dispersion of dotsfrom the discrete dot pattern.

As a thirteenth aspect, in the printing system according to any one ofthe first aspect to the twelfth aspect, the halftone process generationmeans may generate two or more kinds of halftone processing rules ofwhich balances of priority for a plurality of requirements required inthe halftone process are different based on the characteristicparameters.

As a fourteenth aspect, in the printing system according to thethirteenth aspect, the plurality of requirements may include at leasttwo items of image quality, cost, a halftone generating time, a halftoneprocessing time, tolerance to a system error, or tolerance toenvironment change.

As a fifteenth aspect, the printing system according to the thirteenthaspect to the fourteenth aspect may further comprise: halftoneregistration means for registering the two or more kinds of halftoneprocessing rules generated by the halftone process generation means, ascandidates of the halftone process capable of being used in the printingsystem.

As a sixteenth aspect, the printing system according to any one of thethirteenth aspect to the fifteenth aspect may further comprise:halftone-selection-chart output means for outputting a halftoneselection chart including quality comparison and evaluation imageregions of the halftone processes by using the two or more kinds ofhalftone processing rules generated by the halftone process generationmeans.

As a seventeenth aspect, the printing system according to any one of thethirteenth aspect to the sixteenth aspect may further comprise:evaluation value calculation means for calculating an evaluation valuefor quantitatively evaluating at least one item of image quality, cost,a halftone generating time or a halftone processing time of the halftoneprocess defined by the halftone processing rule.

As an eighteenth aspect, the printing system according to theseventeenth aspect may further comprise: information presentation meansfor presenting information of the evaluation value to a user.

As a nineteenth aspect, the printing system according to any one of thethirteenth aspect to the eighteenth aspect may further comprise:halftone selection operating means for performing an operation ofallowing a user to select the kind of the halftone process used inprinting from the kinds of the halftone processes defined by the two ormore kinds of halftone processing rules generated by the halftoneprocess generation means.

As a twentieth aspect, the printing system according to any one of thethirteenth aspect to the nineteenth aspect may further comprise:halftone automatic selection means for automatically selecting the kindof the halftone process used in the printing of the printing system fromthe kinds of the halftone processes defined by the two or more kinds ofhalftone processing rules generated by the halftone process generationmeans based on priority parameters related to priorities for theplurality of requirements.

As a twenty-first aspect, the printing system according to the twentiethaspect may further comprise: a priority input unit for allowing a userto input information related to the priorities for the plurality ofrequirements.

As a twenty-second aspect, in the printing system according to thetwentieth aspect or the twenty-first aspect, the halftone automaticselection means may include determination-evaluation-value calculationmeans for calculating a determination evaluation value for evaluatingadequateness of the halftone process defined by the halftone processingrule generated by the halftone process generation means based on thepriority parameter, and the halftone automatic selection meansautomatically selects the kind of the halftone process used in theprinting of the printing system based on the determination evaluationvalue calculated by the determination-evaluation-value calculationmeans.

As a twenty-third aspect, in the printing system according to any one ofthe twentieth aspect to the twenty-second aspect, the halftone automaticselection means may include simulation image generation means forgenerating a simulation image in a case where a halftone image acquiredby applying the halftone process defined by the halftone processing rulegenerated by the halftone process generation means is printed, andimage-quality-evaluation-value calculation means for calculating animage quality evaluation value from the simulation image.

As a twenty-fourth aspect, the printing system according to any one ofthe twentieth aspect to the twenty-third aspect may further comprise:priority parameter retention means for retaining the priority parameter.

As a twenty-fifth aspect, the printing system according to any one ofthe first aspect to the twenty-fourth aspect may further comprise:setting means for setting parameters related to system errors assumed ina case where printing is performed by the printing system; means forgenerating a simulation image in which the system error indicated by theparameter is reflected; and image quality evaluation means forevaluating image quality of a simulation image in which the system erroris reflected. The parameter may include the characteristic parameters,and the halftone process generation means generates the halftoneprocessing rule based on a simulation image in which the evaluationfalls in a target range.

The “means for generating the simulation image” may serve as the sameprocessing means as the “simulation image generation means” of thetwenty-third aspect, or may be provided as individual processing means.

The “simulation image in which the system error is reflected” refers toa simulation image generated in a condition in which the system error isadded in setting of simulation condition when the simulation image isgenerated.

The “target range” is a predetermined range defined as an image qualitytarget. The target range may be defined as an image quality targetcapable of satisfying required image quality target. The target rangemay be defined as a condition for securing that image quality isfavorable with an allowable level. The target range may include a casewhere an evaluation value as an index for evaluating the image qualityis most favorable.

According to the twenty-fifth aspect, it is possible to generate thehalftone processing rule appropriate for the printing system inconsideration of the system error on the assumption of actual printingperformed by the printing system. Accordingly, it is possible to realizean appropriate halftone process capable of achieving favorable imagequality, and it is possible to acquire a print image having favorableimage quality.

As a twenty-sixth aspect, in the printing system according to thetwenty-fifth aspect, the system error may include characteristic errorsexpected to exhibit reproducibility as the characteristics of theprinting system, and random system errors as irregularly changed errors.

The “expected to exhibit reproducibility” includes a case where theerror has reproducibility and the error is reasonably expected toexhibit reproducibility with a high probability from a statisticalprobability distribution. For example, an average value or a centervalue of a distribution of the measurement values of the system errormay be used as the “characteristic error”.

The “irregularly changed” includes a case where the error is changedtemporally or depending on a place. The irregularly changed error is anerror having reproducibility lower than the characteristic error, andmay be comprehended as a component of “dispersion” for thecharacteristic error form a statistical probability distribution. It isunderstood that the random system error is a change component added tothe characteristic error. As the random system error as the changecomponent added to the characteristic error, there may be both apositive value and a negative value.

As a twenty-seventh aspect, in the printing system according to thetwenty-sixth aspect, a plurality of levels may be determined for valuesof the random system errors, and simulation images for the respectivelevels in which the random system errors corresponding to the pluralityof levels are reflected may be generated by the means for generating thesimulation image.

As a twenty-eighth aspect, in the printing system according to thetwenty-seventh aspect, the plurality of levels may be determinedaccording to a system error distribution of the printing system.

As a twenty-ninth aspect, in the printing system according to thetwenty-eighth aspect, the image quality evaluation means may performimage quality evaluation on the simulation images for the respectivelevels and may calculate an image quality evaluation value acquired byintegrating the image quality evaluation of the simulation images forthe respective levels.

As a thirtieth aspect, in the printing system according to any one ofthe twenty-seventh aspect to the twenty-ninth aspect, the image qualityevaluation means may include calculation means for calculating thesummation of the evaluation values of the simulation images for therespective levels or a weighted sum acquired by multiplying a weightingfactor to the evaluation values of the simulation images for therespective levels, and the weighting factor may be determined accordingto the system error distribution of the printing system.

As a thirty-first aspect, in the printing system according to any one ofthe twenty-fifth aspect to the thirtieth aspect may further comprise: astorage unit that accumulates data of the parameter acquired in thepast. The halftone processing rule may be generated based on theaccumulated data.

As a thirty-second aspect, in the printing system according to thethirty-first aspect, information of the system error distribution of theprinting system may be updated based on the accumulated data.

As a thirty-third aspect, the printing system according to thethirty-first aspect or the thirty-second aspect may further comprise:characteristic parameter update determination means for determiningwhether or not to update the characteristic parameter; and specifiedvalue acquisition means for acquiring a specified value used todetermine whether or not to update the characteristic parameter by thecharacteristic parameter update determination means. The characteristicparameter update determination means may update the characteristicparameter in a case where a difference between a new characteristicparameter acquired by the characteristic parameter acquisition means andan existing characteristic parameter which is stored in the storage unitand is acquired in the past exceeds to the specified value acquired bythe specified value acquisition means.

As a thirty-fourth aspect, in the printing system according to thethirty-third aspect, the characteristic parameter update determinationmeans may determine whether or not to update the characteristicparameter indicating the characteristic error expected to exhibitreproducibility as the characteristics of the printing system.

As a thirty-fifth aspect, in the printing system according to thethirty-third aspect or the thirty-fourth aspect, the characteristicparameter update determination means may determine whether or not toupdate, as the characteristic parameter, at least any one of an averagedot density of the plurality of printing elements, an average dotdiameter of the plurality of printing elements, an average dot shape ofthe plurality of printing elements, landing interference in theplurality of printing elements, a dot density for each printing element,a dot diameter for each printing element, a dot shape for each printingelement, a dot recording position error for each printing element,recording inexecutable abnormality for each printing element, a dotposition shift for each droplet kind, a bidirectional printing positionshift, a bidirectional printing position shift for each droplet kind, ahead vibration error, a transport error of the printing medium, or ahead module vibration error in a head formed using a plurality of headmodules.

As a thirty-sixth aspect, in the printing system according to any one ofthe thirty-third aspect to the thirty-fifth aspect, the specified valueacquisition means may acquire a specified value determined based onaccumulated characteristic parameters.

As a thirty-seventh aspect, in the printing system according to any oneof the thirty-third aspect to the thirty-fifth aspect, the specifiedvalue acquisition means may acquire a specified value determined basedon an irregularly changed error as the characteristics of the printingsystem.

As a thirty-eighth aspect, in the printing system according to any oneof the first aspect to the thirty-seventh aspect, thecharacteristic-parameter-acquisition-chart output means may output acharacteristic parameter acquisition chart together with a continuouslyoutput image, and the characteristic parameter acquisition means mayacquire the characteristic parameters by analyzing the read image of thecharacteristic parameter acquisition chart which is already outputtogether with the image.

As a thirty-ninth aspect, the printing system according to any one ofthe first aspect to the thirty-eighth aspect may further comprise:halftone processing means for performing the halftone process by usingthe halftone processing rule generated by the halftone processgeneration means. The characteristic-parameter-acquisition-chart outputmeans may output the characteristic parameter acquisition chart togetherwith each of a plurality of images, the halftone process generationmeans may generate the halftone processing rule based on the read imageof the characteristic parameter acquisition chart output by thecharacteristic-parameter-acquisition chart output means, and thehalftone processing means may perform the halftone process on theplurality of images using the halftone processing rule generated by thehalftone processing means.

As a fortieth aspect, in the printing system according to thethirty-eighth aspect, the characteristic-parameter-acquisition-chartoutput means may output the characteristic parameter acquisition charttogether with an image output two or more images earlier than the imageon which the halftone process is performed, the characteristic parameteracquisition means may acquire the characteristic parameter by using thecharacteristic parameter acquisition chart together with the imageoutput two or more images earlier than the image on which the halftoneprocess is performed, and the halftone process generation means maygenerate the halftone processing rule by using the characteristicparameter acquisition chart together with the image output two or moreimages earlier than the image on which the halftone process isperformed.

As a forty-first aspect, in the printing system according to thefortieth aspect, any one or more processes of a process of causing thecharacteristic-parameter-acquisition-chart output means to output thecharacteristic parameter acquisition chart, a process of causing usingthe characteristic parameter acquisition means to acquire thecharacteristic parameter, and a process of causing the halftone processgeneration means to generate the halftone processing rule may beperformed in parallel with the halftone process performed by thehalftone processing means for performing the halftone process by usingthe halftone processing rule generated by the halftone processgeneration means.

As a forty-second aspect, the printing system according to any one ofthe first aspect to the forty-first aspect may further comprise: qualityrequest acquisition means for acquiring a quality request for a printimage. The characteristic-parameter-acquisition-chart output means maychange at least any one of the content of the characteristic parameteracquisition chart or an output condition of the characteristic parameteracquisition chart in response to the quality request for the print imageacquired by the quality request acquisition means.

As a forty-third aspect, the printing system according to any one of thefirst aspect to the forty-first aspect may further comprise: qualityrequest acquisition means for acquiring a quality request for a printimage. The image reading means may change a reading condition of thecharacteristic parameter acquisition chart in response to the qualityrequest for the print image acquired by quality request acquisitionmeans.

As a forty-fourth aspect, the printing system according to any one ofthe first aspect to the forty-first aspect may further comprise: qualityrequest acquisition means for acquiring a quality request for a printimage. The characteristic parameter acquisition means may change amethod of acquiring the characteristic parameter in response to thequality request for the print image acquired by the quality requestacquisition means.

As a forty-fifth aspect, the printing system according to any one of thefirst aspect to the forty-first aspect may further comprise: qualityrequest acquisition means for acquiring a quality request for a printimage. The halftone process generation means may change the content ofthe halftone processing rule in response to the quality request for theprint image acquired by the quality request acquisition means.

As a forty-sixth aspect, the printing system according to any one of thefirst aspect to the forty-fifth aspect may further comprise:dot-reproduction-accuracy-investigation-dedicated-chart output means foroutputting a dedicated chart to investigate dot reproduction accuracy;and dot-reproduction-accuracy analysis means for analyzing the dedicatedchart to investigate the dot reproduction accuracy output by thedot-reproduction-accuracy-investigation-dedicated-chart output means.The characteristic-parameter-acquisition-chart output means may changeat least any one of the content of the characteristic parameteracquisition chart or an output condition of the characteristic parameteracquisition chart depending on the analyzing result of thedot-reproduction-accuracy analysis means.

As a forty-seventh aspect, the printing system according to any one ofthe first aspect to the forty-fifth aspect may further comprise:dot-reproduction-accuracy-investigation-dedicated-chart output means foroutputting a dedicated chart to investigate dot reproduction accuracy;and dot-reproduction-accuracy analysis means for analyzing the dedicatedchart to investigate the dot reproduction accuracy output by thedot-reproduction-accuracy-chart output means. The image reading meansmay change a reading condition of the characteristic parameteracquisition chart depending on the analyzing result of thedot-reproduction-accuracy analysis means.

As a forty-eighth aspect, the printing system according to any one ofthe first aspect to the forty-fifth aspect may further comprise:dot-reproduction-accuracy-investigation-dedicated-chart output means foroutputting a dedicated chart to investigate dot reproduction accuracy;and dot-reproduction-accuracy analysis means for analyzing the dedicatedchart to investigate the dot reproduction accuracy output by thedot-reproduction-accuracy-investigation-dedicated-chart output means.The characteristic parameter acquisition means may change a method ofacquiring the characteristic parameter depending on the analyzing resultof the dot-reproduction-accuracy analysis means.

As a forty-ninth aspect, the printing system according to any one of thefirst aspect to the forty-fifth aspect may further comprise:dot-reproduction-accuracy-investigation-dedicated-chart output means foroutputting a dedicated chart to investigate dot reproduction accuracy;and dot-reproduction-accuracy analysis means for analyzing the dedicatedchart to investigate the dot reproduction accuracy output by thedot-reproduction-accuracy-investigation-dedicated-chart output means.The halftone process generation means may change the content of thehalftone processing rule depending on the analyzing result of thedot-reproduction-accuracy analysis means.

As a fiftieth aspect, the printing system according to any one of thefirst aspect to the forty-ninth aspect may further comprise:characteristic parameter storage means for storing characteristicparameters related to a system specification, among the characteristicparameters; and characteristic-parameter-acquisition-chart generationmeans for generating characteristic parameter acquisition charts. Thecharacteristic-parameter-acquisition-chart generation means may generatethe characteristic parameter acquisition chart based on thecharacteristic parameter related to the system specification acquiredfrom the characteristic parameters related to the system specificationstored in the characteristic parameter storage means, thecharacteristic-parameter-acquisition-chart output means may output thecharacteristic parameter acquisition chart generated by thecharacteristic-parameter-acquisition-chart generation means, the imagereading means may read the characteristic parameter acquisition chartoutput by the characteristic-parameter-acquisition-chart output means,and the characteristic parameter acquisition means may acquire thecharacteristic parameters by analyzing the read image of thecharacteristic parameter acquisition chart acquired by the image readingmeans.

As a fifty-first aspect, the printing system according to any one of thefirst aspect to the forty-ninth aspect may further comprise:characteristic parameter storage mans for storing characteristicparameters related to a system specification, among the characteristicparameters; characteristic-parameter-acquisition-chart storage means forstoring the characteristic parameter acquisition charts; andcharacteristic-parameter-acquisition-chart selection means for selectingthe characteristic parameter acquisition chart from the characteristicparameter acquisition charts stored in thecharacteristic-parameter-acquisition-chart storage means. Thecharacteristic-parameter-acquisition-chart selection means may selectthe characteristic parameter acquisition chart based on thecharacteristic parameter related to the system specification acquiredfrom the characteristic parameters related to the system specificationstored in the characteristic parameter storage means, thecharacteristic-parameter-acquisition-chart output means may output thecharacteristic parameter acquisition chart selected by thecharacteristic-parameter-acquisition-chart selection means, the imagereading means may read the characteristic parameter acquisition chartoutput by the characteristic-parameter-acquisition-chart output means,and the characteristic parameter acquisition means may acquire thecharacteristic parameters by analyzing the read image of thecharacteristic parameter acquisition chart acquired by the image readingmeans.

As a method of generating a halftone processing rule according to afifty-second aspect is a method of generating a halftone processing rulecomprising: a characteristic-parameter-acquisition-chart output step ofoutputting a characteristic parameter acquisition chart including apattern for acquiring characteristic parameters related tocharacteristics of a printing system; an image reading step of readingthe characteristic parameter acquisition chart output in thecharacteristic-parameter-acquisition-chart output step; a characteristicparameter acquisition step of acquiring the characteristic parameters byanalyzing a read image of the characteristic parameter acquisition chartacquired in the image reading step; and a halftone process generationstep of generating halftone processing rule that define halftoneprocesses used in the printing system based on the characteristicparameters acquired in the characteristic parameter acquisition step.

In the fifty-second aspect, it is possible to appropriately combine thesame matters as the matters specified in the second aspect to thefifty-first aspect. In this case, a processing unit or a functional unit(means) as means serving as the process or function specified in theprinting system may be comprehended as an element of a “step” of acorresponding process or operation.

An image processing device according to a fifty-third aspect is an imageprocessing device comprising: characteristic-parameter-acquisition-chartgeneration means for generating chart data of a characteristic parameteracquisition chart including a pattern for acquiring characteristicparameters related to characteristics of a printing system;characteristic parameter acquisition means for acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart printed by the printingsystem based on the chart data; and halftone process generation meansfor generating halftone processing rules that define the processingcontents of halftone processes used in the printing system based on thecharacteristic parameters acquired by the characteristic parameteracquisition means.

According to the fifty-third aspect, the characteristic parameteracquisition chart is output by the printing system based on the chartdata of the characteristic parameter acquisition chart generated by theimage processing device. The output characteristic parameter acquisitionchart is read by the image reading means, and thus, the read image ofthe characteristic parameter acquisition chart is acquired. The imageprocessing device acquires the information of the characteristicparameter by analyzing the read image of the characteristic parameteracquisition chart, and generates the halftone processing rule based onthe acquired characteristic parameter.

According to the image processing device according to the fifty-thirdaspect, it is possible to simply set the characteristic parameter of theprinting system without giving an excessive load to the user, and it ispossible to generate the halftone processing rule appropriate for thecharacteristics of the printing system.

In the fifty-third aspect, it is possible to appropriately combine thesame matters as the matters specified in the second aspect to thefifty-first aspect.

A program according to a fifty-fourth aspect is a program causing acomputer to function as: characteristic-parameter-acquisition-chartgeneration means for generating chart data of a characteristic parameteracquisition chart including a pattern for acquiring characteristicparameters related to characteristics of a printing system;characteristic parameter acquisition means for acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart printed by the printingsystem based on the chart data; and a halftone process generation meansfor generating halftone processing rules that define the processingcontents of halftone processes used in the printing system based on thecharacteristic parameters acquired by the characteristic parameteracquisition means.

It is possible to appropriately combine the same matters as the mattersspecified in the second aspect to the fifty-first aspect with theprogram according to the fifty-fourth aspect. In this case, a processingunit or a functional unit (means) as means serving as the process orfunction specified in the printing system may be comprehended as anelement of a program for realizing means of a corresponding process oroperation.

A printing system according to a fifty-fifth aspect is a printing systemcomprising: printing mode selection means for selecting a printing modeof a printing system; characteristic-parameter-acquisition-chart outputmeans for outputting a characteristic parameter acquisition chart whichincludes a pattern for acquiring characteristic parameters related tocharacteristics of the printing system, the characteristic parameteracquisition chart being for use in the printing mode selected by theprinting mode selection means; chart-output-condition setting means forsetting a chart output condition when the characteristic parameteracquisition chart is output by thecharacteristic-parameter-acquisition-chart output means, thechart-output-condition setting means setting the chart output conditiondepending on the printing mode selected by the printing mode selectionmeans; image reading means for reading the characteristic parameteracquisition chart output by thecharacteristic-parameter-acquisition-chart output means; andcharacteristic parameter acquisition means for acquiring thecharacteristic parameter by analyzing a read image of the characteristicparameter acquisition chart acquired by the image reading means.

According to the fifty-fifth aspect, since the output condition of thecharacteristic parameter acquisition chart including the pattern foracquiring the characteristic parameters is set depending on the setprinting mode, it is possible to output the characteristic parameteracquisition chart on which the characteristics of the printing systemfor each printing mode are reflected, and it is possible toappropriately comprehend the characteristics of the printing system foreach printing mode.

In the fifty-fifth aspect, since the optimized characteristic parameteracquisition chart can be output, in a case where the characteristicparameter acquisition chart is reduced, it is possible to reduce theprocessing time when the characteristic parameter acquisition chart isoutput, it is possible to reduce the amount of the printing medium onwhich the characteristic parameter acquisition chart is output, and itis possible to reduce the amount of ink.

As a fifty-sixth aspect, in the printing system according to thefifty-fifth aspect, the chart-output-condition setting means may set atleast one of a chart item related to the content of the characteristicparameter acquisition chart or a scanning condition related to anoperation of the characteristic-parameter-acquisition-chart output meanswhen the chart output condition is set.

As a fifty-seventh aspect, the printing system according to thefifty-sixth aspect may further comprise: a recording head that includesa plurality of printing elements which jets a liquid. Thechart-output-condition setting means may set, as the chart item, atleast any one of the kind of the liquid used to output thecharacteristic parameter acquisition chart, the kind of a liquid dropletof the liquid used to output the characteristic parameter acquisitionchart, or the printing element used to output the characteristicparameter acquisition chart, when the chart output condition is set.

As a fifty-eighth aspect, in the printing system according to thefifty-seventh aspect, the recording head may be a serial scan typerecording head that jets the liquid while scanning in a main scanningdirection, and the chart-output-condition setting means may set, as thescanning condition, at least any one of a scanning speed applied to theoutputting of the characteristic parameter acquisition chart, thetransport amount of the printing medium applied to the outputting of thecharacteristic parameter acquisition chart, a jetting frequency appliedto the outputting of the characteristic parameter acquisition chart, ora scanning type applied to the outputting of the characteristicparameter acquisition chart, when the chart output condition is set.

As a fifty-ninth aspect, the printing system according to thefifty-sixth aspect may further comprise: a serial scan type recordinghead that includes a plurality of printing elements which jets a liquiddroplet, the recording head jetting a liquid while scanning in a mainscanning direction. The chart-output-condition setting means may set, asthe scanning condition, at least any one of a scanning speed applied tothe outputting of the characteristic parameter acquisition chart, thetransport amount of a printing medium applied to the outputting of thecharacteristic parameter acquisition chart, a jetting frequency appliedto the outputting of characteristic parameter acquisition chart, or ascanning type applied to the outputting of the characteristic parameteracquisition chart, when the chart output condition is set.

As a sixtieth aspect, in the printing system according to thefifty-eighth aspect or the fifty-ninth aspect, thechart-output-condition setting means may set, as the scanning type, atleast one of unidirectional scanning, bidirectional scanning, or thenumber of scanning paths, when the chart output condition is set.

As a sixty-first aspect, the printing system according to any one of thefifty-fifth aspect to the sixtieth aspect may further comprise: halftoneprocess generation means for generating halftone processing rules thatdefine the processing contents of halftone processes used in theprinting system based on the characteristic parameters acquired by thecharacteristic parameter acquisition means.

As a sixty-second aspect, the printing system according to any one ofthe fifty-fifth aspect to the sixty-first aspect may further comprise:error message display means for displaying an error message indicatingthat the occurrence of an error in the printing system, which isdetermined based on the characteristic parameters acquired by thecharacteristic parameter acquisition means.

A method of acquiring a characteristic parameter according to asixty-third aspect is a method of acquiring a characteristic parameter.The method comprises: a printing mode selection step of selecting aprinting mode of a printing system; acharacteristic-parameter-acquisition-chart output step of outputting acharacteristic parameter acquisition chart which includes a pattern foracquiring characteristic parameters related to characteristics of theprinting system, the characteristic parameter acquisition chart beingfor use in the printing mode selected in the printing mode selectionstep; a chart-output-condition setting step of setting a chart outputcondition when the characteristic parameter acquisition chart is outputin the characteristic-parameter-acquisition-chart output step, thechart-output-condition setting step setting the chart output conditiondepending on the printing mode selected in the printing mode selectionstep; an image reading step of reading the characteristic parameteracquisition chart output in thecharacteristic-parameter-acquisition-chart output step; and acharacteristic parameter acquisition step of acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart acquired in the image readingstep.

In the sixty-third aspect, it is possible to appropriately combine thesame matters as the matters specified in the fifty-sixth aspect to thesixty-second aspect. In this case, a processing unit or a functionalunit (means) as means serving as the process or function specified inthe printing system may be comprehended as an element of a “step” of acorresponding process or operation.

An image processing device according to a sixty-fourth aspect is animage processing device comprising: printing mode selection means forselecting a printing mode of a printing system;characteristic-parameter-acquisition-chart output means for outputting acharacteristic parameter acquisition chart which includes a pattern foracquiring characteristic parameters related to characteristics of theprinting system, the characteristic parameter acquisition chart beingfor use in the printing mode selected by the printing mode selectionmeans; chart-output-condition setting means for setting a chart outputcondition when the characteristic parameter acquisition chart is outputby the characteristic-parameter-acquisition chart output means, thechart-output-condition setting means setting the chart output conditiondepending on the printing mode selected by the printing mode selectionmeans; image reading means for reading the characteristic parameteracquisition chart output by thecharacteristic-parameter-acquisition-chart output means; andcharacteristic parameter acquisition means for acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart acquired by the image readingmeans.

In the sixty-fourth aspect, it is possible to appropriately combine thesame matters as the matters specified in the fifty-sixth aspect to thesixty-second aspect.

A program according to a sixty-fifth aspect is a program causing acomputer to function as: printing mode selection means for selecting aprinting mode of a printing system;characteristic-parameter-acquisition-chart output means for outputting acharacteristic parameter acquisition chart which includes a pattern foracquiring characteristic parameters related to characteristics of theprinting system, the characteristic parameter acquisition chart beingfor use in the printing mode selected by the printing mode selectionmeans; chart-output-condition setting means for setting a chart outputcondition when the characteristic parameter acquisition chart is outputby the characteristic-parameter-acquisition chart output means, thechart-output-condition setting means setting the chart output conditiondepending on the printing mode selected by the printing mode selectionmeans; image reading means for reading the characteristic parameteracquisition chart output by thecharacteristic-parameter-acquisition-chart output means; andcharacteristic parameter acquisition means for acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart acquired by the image readingmeans.

In the sixty-fifth aspect, it is possible to appropriately combine thesame matters as the matters specified in the fifty-sixth aspect to thesixty-second aspect. In this case, it is possible to appropriatelycombine the same matters as the matters specified in the fifty-sixthaspect to the sixty-second aspect with the program according to thesixty-fifth aspect. In this case, a processing unit or a functional unit(means) as means serving as the process or function specified in theprinting system may be comprehended as an element of a program forrealizing means of a corresponding process or operation.

As an image processing device according to a sixty-sixth aspect is animage processing device comprising: setting means for setting parametersrelated to system errors assumed in a case where printing is performedby a printing system; simulation image generation means for generating asimulation image in which the system error indicated by the parameter isreflected; image quality evaluation means for evaluating image qualityof the simulation image; and halftone process generation means forgenerating halftone processing rules that defines the processingcontents of halftone processes used in the printing system based on thesimulation image in which the evaluation falls in a target range.

The “simulation image in which the system error is reflected” refers toa simulation image generated in a condition in which the system error isadded in setting of simulation condition when the simulation image isgenerated.

The “target range” is a predetermined range defined as an image qualitytarget. The target range may be defined as an image quality targetcapable of satisfying required image quality target. The target rangemay be defined as a condition for securing that image quality isfavorable with an allowable level. The target range may include a casewhere an evaluation value as an index for evaluating the image qualityis most favorable.

According to the sixty-sixth aspect, it is possible to generate thehalftone processing rule appropriate for the printing system inconsideration of the system error on the assumption of actual printingperformed by the printing system. Accordingly, it is possible to realizean appropriate halftone process capable of achieving favorable imagequality, and it is possible to acquire a print image having favorableimage quality.

As a sixty-seventh aspect, in the image processing device according tothe sixty-sixth aspect, the image quality evaluation means may calculatean image quality evaluation value of the simulation image.

As a sixty-eighth aspect, the image processing device according to thesixty-sixth aspect to the sixty-seventh aspect may further comprise:parameter acquisition means for acquiring the parameter related to thesystem error.

As a sixty-ninth aspect, the image processing device according to thesixty-eighth aspect may further comprise: information input means, asthe parameter acquisition means, for allowing the user to input theparameter.

As a seventieth aspect, in the image processing device according to thesixty-ninth aspect, the information input means may include averagevalue input means for inputting an average value of the parameters in aplurality of printing elements provided in the printing system or anaverage equivalent value which is a value equivalent to the averagevalue, or an average value of errors due to the vibration of a recordinghead provided in the printing system or an average equivalent valuewhich is a value equivalent to the average value, and a deviation inputmeans for inputting a deviation from the average value or the averageequivalent value.

According to the seventieth aspect, it is possible to save an input loadof the parameter without giving an excessive operation load in inputtingof the parameter unlike the aspect in which the parameters areindividually input for the plurality of printing elements.

It is preferable that average value display means for displaying theinput average value (or the average equivalent value) and deviationdisplay means for displaying a deviation are provided.

As an example of the parameter for inputting the average value or theaverage equivalent value and the deviation, there is an individualparameter of the printing element. As an example of the individualparameter of the printing element, there are a dot density, a dotdiameter (a diameter of a dot), a dot shape, a dot forming positionshift and a position shift for each droplet kind.

As a seventy-first aspect, the image processing device according to anyone of the sixty-eighth aspect to the seventieth aspect may furthercomprise: image analysis means, as the parameter acquisition means, foracquiring the parameters by analyzing a read image of a characteristicparameter acquisition chart printed by the printing system.

As a seventy-second aspect, in the image processing device according tothe seventy-first aspect, the characteristic parameter acquisition chartmay include a continuous dot pattern in which two or more dots arerecorded so as to be in contact, and the characteristic parameteracquisition means acquires a parameter related to landing interferencefrom the continuous dot pattern.

As a seventy-third aspect, in the image processing device according tothe seventy-second aspect, the characteristic parameter acquisitionchart may include multiple kinds of continuous dot patterns in which atleast one of an inter-dot distance between the two or more dots or arecording time difference between the two or more dots isdifferentiated.

As a seventy-fourth aspect, in the image processing device according toany one of the sixty-sixth aspect to the seventy-third aspect, thesystem errors may be characteristic errors expected to exhibitreproducibility as the characteristics of the printing system.

The “expected to exhibit reproducibility” includes a case where theerror has reproducibility and the error is reasonably expected toexhibit reproducibility with a high probability from a statisticalprobability distribution. For example, an average value or a centervalue of a distribution of the measurement values of the system errormay be used as the “characteristic error”.

As a seventy-fifth aspect, in the image processing device according toany one of the sixty-sixth aspect to the seventy-third aspect, thesystem errors may include characteristic errors expected to exhibitreproducibility as the characteristics of the printing system, andrandom system errors as irregularly changed errors.

The “irregularly changed” includes a case where the error is changedtemporally or depending on a place. The irregularly changed error is anerror having reproducibility lower than the characteristic error, andmay be comprehended as a component of “dispersion” for thecharacteristic error form a statistical probability distribution. It isunderstood that the random system error is a change component added tothe characteristic error. As the random system error as the changecomponent added to the characteristic error, there may be both apositive value and a negative value.

As a seventy-sixth aspect, in the image processing device according tothe seventy-fifth aspect, a plurality of levels may be determined forvalues of the random system errors, and simulation images for therespective levels in which the random system errors corresponding to theplurality of levels are reflected may be generated by the simulationimage generation means.

As a seventy-seventh aspect, in the image processing device according tothe seventy-sixth aspect, the plurality of levels may be determinedaccording to a system error distribution of the printing system.

As a seventy-eighth aspect, in the image processing device according tothe seventy-sixth aspect to the seventy-seventh aspect, the imagequality evaluation means may perform image quality evaluation on thesimulation images for the respective levels and may calculate an imagequality evaluation value acquired by integrating the image qualityevaluation of the simulation images for the respective levels.

As a seventy-ninth aspect, in the image processing device according toany one of the seventy-sixth aspect to the seventy-eighth aspect, theimage quality evaluation means may include calculation means forcalculating the summation of the evaluation values of the simulationimages for the respective levels or a weighted sum acquired bymultiplying a weighing factor to the evaluation values of the simulationimages for the respective levels, and the weighting factor is determinedaccording to the system error distribution of the printing system.

As an eightieth aspect, the image processing device according to any oneof the sixty-sixth aspect to the seventy-ninth aspect may furthercomprise: a storage unit that accumulates data of the parameter acquiredin the past. The halftone processing rule may be generated based on theaccumulated data.

As an eighty-first aspect, in the image processing device according tothe eightieth aspect, information of the system error distribution ofthe printing system may be updated based on the accumulated data.

As an eighty-second aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-first aspect, thesimulation image generation means may generate a simulation image inwhich the influence of the landing interference is reflected.

As an eighty-third aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-second aspect, thesimulation image generation means may generate a simulation image whichincludes a plurality of colors, the simulation image being generated byreflecting the influence of the landing interference between the colors.

As an eighty-fourth aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-third aspect, thesimulation image generation means may generate a simulation image whichincludes dots corresponding to multiple droplet kinds, the simulationimage being generated by reflecting the influence of landinginterference caused by the droplet kind.

As an eighty-fifth aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-fourth aspect, thesimulation image generation means may generate a simulation image inwhich the influence of landing interference caused by an inter-dotinterference is reflected.

As an eighty-sixth aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-fifth aspect, thesimulation image generation means may generate a simulation image inwhich the influence of landing interference caused by a jetting timedifference is reflected.

As an eighty-seventh aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-sixth aspect, thesimulation image generation means may generate a simulation image inwhich at least any one of a change in inter-dot distance, a change indot density, or a change in dot shape is reflected as the influence ofthe landing interference.

As an eighty-eighth aspect, the image processing device according to anyone of the sixty-sixth aspect to the eighty-sixth aspect may furthercomprise: inter-dot contact determination means for determining whetheror not dots are in contact. The simulation image generation means maygenerate a simulation image in which the influence of the landinginterference is reflected on dots determined to be in contact by theinter-dot contact determination means.

As an eighty-ninth aspect, in the image processing device according toany one of the sixty-sixth aspect to the eighty-eighth aspect, thesimulation image generation means may calculate a vector summationacquired by adding vectors indicated by directions from a given dotwhich is a target dot on which the influence of the landing interferenceis reflected toward surrounding dots having a possibility that thelanding interference with the given dot occurs and distances between thegiven dot and the surrounding dots, and may generate a simulation imagein which the influence of the landing interference of the given dot isreflected using the calculated vector summation.

As a ninetieth aspect, in the image processing device according to anyone of the sixty-sixth aspect to the eighty-ninth aspect, the simulationimage generation means may generate a simulation image in serialscanning type printing performed using a plurality of scanning paths,may reflect the influence of the landing interference on dots jettedalong each scanning path when the simulation image is generated, and mayrepeat the reflection of the landing interference for the respectivescanning paths.

As a ninety-first aspect, in the image processing device according toany one of the sixty-sixth aspect to the ninetieth aspect, thesimulation image generation means may generate a high-resolutionsimulation image through the halftone processing result.

A printing system according to a ninety-second aspect is a printingsystem comprising: the image processing device according to any one ofthe sixty-sixth aspect to the ninety-first aspect; and a printing devicethat performs printing on a printing medium based on a halftone imagegenerated through a halftone process defined by a halftone processingrule.

A printing system according to a ninety-third aspect is a printingsystem comprising: setting means for setting a parameter related to asystem error assumed in a case where printing is performed by a printingsystem; simulation image generation means for generating a simulationimage in which the system error indicated by the parameter is reflected;image quality evaluation means for evaluating image quality of thesimulation image; halftone process generation means for generatinghalftone processing rules that define the processing contents ofhalftone processes used in the printing system based on the simulationimage in which the evaluation falls in a target range; and a printingdevice that performs printing on a printing medium based on a halftoneimage generated through the halftone process defined by the halftoneprocessing rule.

A method of generating a halftone processing rule according to aninety-fourth aspect is a method of generating a halftone processingrule. The method comprises: a setting step of setting a parameterrelated to a system error assumed in a case where printing is performedby a printing system; a simulation image generation step of generating asimulation image in which the system error indicated by the parameter isreflected; an image quality evaluation step of evaluating image qualityof the simulation image; and a halftone process generation step ofgenerating halftone processing rules that define the processing contentsof halftone processes used in the printing system based on thesimulation image in which the evaluation falls in a target range.

It is possible to appropriately combine the same matters as the mattersspecified in the sixty-seventh aspect to the ninety-first aspect withthe ninety-fourth aspect. In this case, a processing unit or afunctional unit (means) as means serving as the process or functionspecified in the printing system may be comprehended as an element of a“step” of a corresponding process or operation. The method of generatingthe halftone processing rule according to the ninety-fourth aspect maybe comprehended as the invention of the method of producing the halftoneprocessing rule. The halftone processing rule may be comprehended asinformation provided for the halftone process and is equivalent to aprogram. Accordingly, the ninety-fourth aspect may be interpreted as themethod of producing the halftone processing rule.

A ninety-fifth aspect is a halftone processing rule generated byperforming the method of generating a halftone processing rule accordingto the ninety-fourth aspect.

The halftone processing rule may be specified by the combination of thehalftone algorithm and the halftone parameter. As an example of thehalftone processing rule, there are a dither mask of the dither method,an error diffusion matrix or information of an applied gradation rangein the error diffusion method, and the number of times pixels areupdated and an exchange pixel range in the direct binary search method.

According to the halftone processing rule according to the ninety-fifthaspect, it is possible to generate a target image having favorable imagequality.

An image processing method of generating a halftone image according to aninety-sixth aspect is an image processing method of generating ahalftone image by performing a halftone process defined by a halftoneprocessing rule generated by performing the method of generating ahalftone processing rule according to the ninety-fourth aspect.

The image processing method according to the ninety-sixth aspect may becomprehend as the invention of the method of producing the halftoneimage. The “halftone image” may be a form of image data as informationprovided for a printing control process, or may be a form of a printimage printed according to the image data. The ninety-sixth aspect maybe interpreted as the method of producing the halftone image.

A ninety-seventh aspect is a halftone image generated by performing ahalftone process defined by a halftone processing rule generated byperforming the method of generating a halftone processing rule accordingto the ninety-fourth aspect.

A ninety-eighth aspect is a printed material manufacturing method ofacquiring a printed material by performing printing on a printing mediumbased on a halftone image generated through a halftone process definedby a halftone processing rule generated by performing the method ofgenerating a halftone processing rule according to the ninety-fourthaspect.

According to the ninety-eighth aspect, it is possible to produce afavorable printed material falling in a target range of image quality.

A program according to the ninety-ninth aspect is a program causing acomputer to function as: setting means for setting a parameter relatedto a system error assumed in a case where printing is performed by aprinting system; simulation image generation means for generating asimulation image in which the system error indicated by the parameter isreflected; image quality evaluation means for evaluating image qualityof the simulation image; and halftone process generation means forgenerating halftone processing rules that define the processing contentsof halftone processes used in the printing system based on thesimulation image in which the evaluation falls in a target range.

It is possible to appropriately combine the same matters as the mattersspecified in the sixty-seventh aspect to the ninety-first aspect to theninety-ninth aspect. In this case, means serving as the process orfunction specified in the image processing device may be comprehended asan element of a program for realizing means of a corresponding processor operation.

An image processing device according to one hundredth aspect is an imageprocessing device that performs at least one of a process of generatinghalftone processing rules which define the contents of halftoneprocesses used in an ink jet printing system and the halftone process.The device comprises: analysis means for analyzing a contact state ofeach dot of a plurality of pixels of a dot image indicating a dotarrangement form with another dot; landing-interference-influenceevaluation means for calculating a landing interference evaluation valuefor evaluating the degree of influence of dot movement due to landinginterference based on information indicating the contact state acquiredby the analysis means; and signal processing means for performing atleast one process of a process of generating a halftone parameter of thehalftone processing rule or a process of generating a halftone imagethrough the halftone process by using the landing interferenceevaluation value calculated by the landing-interference-influenceevaluation means or using an evaluation value generated based on thelanding interference evaluation value calculated by thelanding-interference-influence evaluation means.

As the “plurality of pixels of the dot image”, all pixels constitutingthe dot image may be used as targets, or some of the plurality of pixelsconstituting the dot image may be used as targets.

The “contact state” refers to a contact direction and/or a contactamount. The “landing interference evaluation value” is an evaluationvalue for quantitatively representing the degree of influence of dotmovement by a value. The influence of the dot movement is quantitativelyevaluated by the landing interference evaluation value. The “evaluationvalue generated based on the landing interference evaluation value” isanother evaluation value two-dimensionally generated based on thelanding interference evaluation value. The “evaluation value generatedbased on the landing interference evaluation value” is a value in whichthe landing interference evaluation value is reflected.

The “using the landing interference evaluation value or using theevaluation value generated based on the landing interference evaluationvalue” includes a case where a processing result of a process ofcomparing the “landing interference evaluation value” or the “evaluationvalue generated based on the landing interference evaluation value” witha certain specified value (for example, specified reference value), aprocess of comprehending an increase/decrease tendency of the “landinginterference evaluation value” or the “evaluation value generated basedon the landing interference evaluation value” by comparing the value ofthe “landing interference evaluation value” calculated from differentdot images or the “evaluation value generated based on the landinginterference evaluation value”, or a combination process thereof isused.

The halftone processing rule may be specified by the combination of thehalftone algorithm and the halftone parameter. As an example of thehalftone processing rule, there are a dither mask of the dither method,an error diffusion matrix or information of an applied gradation rangein the error diffusion method, and the number of times pixels areupdated and an exchange pixel range in the direct binary search method.

According to the one hundredth aspect, it is possible to quantitativelyevaluating the influence of the dot movement due to the landinginterference by using the landing interference evaluation value, and itis possible to acquire the halftone parameter and/or the halftone imagein which the influence of the image quality of the dot movement due tothe landing interference is relatively less. According to the onehundredth aspect, it is possible to suppress the image qualitydeterioration caused by the landing interference, and it is possible togenerate an image having high image quality.

As one hundred-first aspect, in the image processing device according tothe one hundredth aspect, the signal processing means may generate atleast one of the halftone parameter or the halftone image havingtolerance to the dot movement due to the landing interference based on aresult of a comparison process using the landing interference evaluationvalue or the evaluation value generated based on the landinginterference evaluation value.

The “halftone image having tolerance to the dot movement due to thelanding interference” means that the image has robustness such that anequivalent image quality level to the landing interference phenomenon ismaintained, in other words, means that the image has fastness such thatthe image quality deterioration due to the landing interference falls inan allowable range.

The “specified reference value” may be appropriately set in terms of anallowable range of the landing interference evaluation value or anallowable range of the target image quality. The reference valuecompared with the landing interference evaluation value and thereference value compared with the evaluation value generated based onthe landing interference evaluation value may be set to be differentreference values.

As one hundred-second aspect, in the image processing device accordingto the one hundred-third aspect, the comparison process may include aprocess of comparing the landing interference evaluation value with aspecified reference value or a process of comparing the evaluation valuegenerated based on the landing interference evaluation value with aspecified reference value, and the signal processing means may performat least one of a process of generating the halftone parameter such thatdot arrangement falls in an allowable range indicated by the specifiedreference value or a process of generating the halftone image such thatdot arrangement falls in an allowable range indicated by the specifiedreference value, based on the comparing result of the comparisonprocess.

As one hundred-third aspect, in the image processing device according tothe one hundred-second aspect, the signal processing means may generateat least one of the halftone parameter or the halftone image in whichthe degree of influence of the dot movement due to the landinginterference is equal to or less than the degree of influence of the dotmovement indicated by the specified reference value by comparing thelanding interference evaluation value with the specified referencevalue.

As one hundred-fourth aspect, the image processing device according toany one of the one hundredth aspect to the one hundred-third aspect mayfurther comprise: movement amount calculation means for calculating themovement amount of the dot movement due to the landing interferencebased on the information indicating the contact state acquired by theanalysis means. The landing-interference-influence evaluation means maycalculate the landing interference evaluation value based on informationindicating the movement amount calculated by the movement amountcalculation means.

The movement amount of the dot movement due to the landing interferenceis described as a “landing interference movement amount” in some cases.The landing interference evaluation value may be directly calculatedfrom the information indicating the contact state, or the landinginterference evaluation value may be calculated from the informationindicating the landing interference movement amount by acquiring thelanding interference movement amount based on the information indicatingthe contact state, as in the fifth aspect.

As one hundred-fifth aspect, the image processing device according toany one of the one hundredth aspect to the one hundred-third aspect mayfurther comprise: error reflection processing means for generating thedot arrangement on which at least one error of a dot diameter, a dotshape, a dot forming position shift, or non-jetting is reflected as anerror of the ink jet printing system. The analysis means may analyze thecontact state of the dot on which the error is reflected with anotherdot, and the landing-interference-influence evaluation means maycalculate the landing interference evaluation value for evaluating thedegree of influence of the dot movement due to the landing interferencein a case where the error is reflected.

As one hundred-sixth aspect, in the image processing device according tothe one hundred-fifth aspect, the analysis means may perform a processof analyzing the contact state in a case where the non-reflection of theerror is performed and in a case where the error is reflected, and thelanding-interference-influence evaluation means may calculate a firstlanding interference evaluation value as the landing interferenceevaluation value for evaluating the degree of influence of the dotmovement due to the landing interference in the case where thenon-reflection of the error is performed, and may calculate a secondlanding interference evaluation value as the landing interferenceevaluation value for evaluating the degree of influence of the dotmovement due to the landing interference in the case where the error isreflected.

The “case where the non-reflection of the error is performed” refers toa case where the error is not reflected”. A case where the error is notreflected is equivalent to a state before the error is reflected. Theexpression of “the error is reflected” means that an error component isadded to the dot image, and is a synonym for the addition of the error.

The first landing interference evaluation value and the second landinginterference evaluation value may be used as the “landing interferenceevaluation value”. The first evaluation value may be generated based onthe first landing interference evaluation value, and the secondevaluation value may be generated based on the second landinginterference evaluation value.

The first evaluation value and the second evaluation value may be usedas the “evaluation value”, and a new “evaluation value” may be generatedby combining the first evaluation value and the second evaluation value.

As one hundred-seventh aspect, in the image processing device accordingto the one hundred-fifth aspect, the analysis means may perform aprocess of analyzing the contact state in a case where thenon-reflection of the error is performed and in a case where the erroris reflected, the landing-interference-influence evaluation means maycalculate a first landing interference evaluation value for evaluatingthe degree of influence of the dot movement due to the landinginterference in the case where the non-reflection of the error isperformed, and may calculate a second landing interference evaluationvalue for evaluating the degree of influence of the dot movement due tothe landing interference in the case where the error is reflected, andthe landing-interference-influence evaluation means may calculate thelanding interference evaluation value from a weighted sum of the firstlanding interference evaluation value and the second landinginterference evaluation value.

As one hundred-eighth aspect, the image processing device according toany one of the one hundred-fifth aspect to the one hundred-seventhaspect may further comprise: movement amount calculation means forcalculating the movement amount of the dot movement due to the landinginterference based on the information indicating the contact stateacquired by the analysis means. The landing-interference-influenceevaluation means may calculate the landing interference evaluation valuebased on information indicating the movement amount calculated by themovement amount calculation means.

As one hundred-ninth aspect, in the image processing device according tothe one hundred-eighth aspect, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefrom information indicating the movement amount of only a dot group onwhich the error is reflected.

According to the one hundred-ninth aspect, it is possible to reduce acalculation amount, and it is possible to simply evaluate the influenceof the landing interference.

As one hundred-tenth aspect, in the image processing device according tothe one hundred-eighth aspect or the one hundred-ninth aspect, in a casewhere the dot forming position shift is reflected as the error, thelanding-interference-influence evaluation means may calculate thelanding interference evaluation value from only the movement amount in adirection parallel to a direction to which the error due to the dotforming position shift is applied, among directions of the dot movementdue to the landing interference.

As one hundred-eleventh aspect, in the image processing device accordingto any one of the one hundred-fourth aspect and the one hundred-eighthaspect to the one hundred-tenth aspect, thelanding-interference-influence evaluation means may calculate thelanding interference evaluation value from only the movement amount in adirection perpendicular to a scanning direction of the ink jet printingsystem, among directions of the dot movement due to the landinginterference.

An ink jet printing system according to one hundred-twelfth aspect is anink jet printing system comprising: the image processing deviceaccording to any one of the one hundredth aspect to the onehundred-eleventh aspect; and an ink jet printing device that performsprinting on a printing medium based on a halftone image generatedthrough a halftone process determined by the halftone processing rule ora halftone image generated by the signal processing means.

An image processing method according to one hundred-thirteenth aspect isan image processing method of performing at least one process of aprocess of generating halftone processing rules that define the contentsof halftone processes used in an ink jet printing system or the halftoneprocess. The method comprises: an analysis step of analyzing a contactstate of each dot of a plurality of pixels of a dot image indicating adot arrangement form with another dot; a landing-interference-influenceevaluation step of calculating a landing interference evaluation valuefor evaluating the degree of influence of dot movement due to landinginterference based on information indicating the contact state acquiredin the analysis step; and a signal processing step of performing atleast one process of a process of generating a halftone parameter of thehalftone processing rule or a process of generating a halftone imagethrough the halftone process by using an evaluating result of thelanding interference evaluation value calculated in thelanding-interference-influence evaluation step or using an evaluatingresult of an evaluation value generated based on the landinginterference evaluation value calculated in thelanding-interference-influence evaluation step.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-first aspect to the one hundred-twelfthaspect with the one hundred-thirteenth aspect. In this case, meansserving as the process or function specified in the image processingdevice may be comprehended as an element of a “step” of a correspondingprocess or operation.

The image processing method according to the one hundred-thirteenthaspect in a case where the image processing step performs the process ofgenerating the halftone parameter of the halftone processing rule may becomprehended as the invention of the method of producing the halftoneprocessing rule. The halftone processing rule is information providedfor the halftone process and is equivalent to a program. Accordingly,the image processing method according to the one hundred-thirteenthaspect in a case where the signal processing step of generating thehalftone parameter is provided may be interpreted as the invention ofthe method of generating the halftone processing rule.

The image processing method according to the one hundred-thirteenthaspect in a case where the signal processing step performs the halftoneprocess of generating the halftone image may be comprehended as theinvention of the halftone processing method, or may be comprehended asthe invention of the method of generating the halftone image. The“halftone image” may be a form of image data as information provided forthe printing control process, or may be a form of the print imageprinted according to the image data. The image processing methodaccording to the one hundred-thirteenth aspect in a case where thesignal processing step of generating the halftone image is provided maybe interpreted as the invention of the method of producing the halftoneimage.

A program according to one hundred-fourteenth aspect is a programcausing a computer to function as an image processing device thatperforms at least one process of a process of generating halftoneprocessing rules that define the contents of halftone processes used inan ink jet printing system or the halftone process. The program causingthe computer to function as: analysis means for analyzing a contactstate of each dot of a plurality of pixels of a dot image indicating adot arrangement form with another dot; landing-interference-influenceevaluation means for calculating a landing interference evaluation valuefor evaluating the degree of influence of dot movement due to landinginterference based on information indicating the contact state acquiredby the analysis means; and signal processing means for performing atleast one process of a process of generating a halftone parameter of thehalftone processing rule or a process of generating a halftone imagethrough the halftone process by using the landing interferenceevaluation value calculated by the landing-interference-influenceevaluation means or using an evaluation value generated based on thelanding interference evaluation value calculated by thelanding-interference-influence evaluation means.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-first aspect to the one hundred-twelfthaspect to the one hundred-fourteenth aspect. In this case, means servingas the process or function specified in the image processing device maybe comprehended as an element of a program for realizing means of acorresponding process or operation.

An image processing device according to one hundred-fifteenth aspect isan image processing device comprising: error reflection processing meansfor generating the dot arrangement in which at least one error of a dotdiameter, a dot shape, a dot forming position shift or non-jetting whichis an element of an error of an ink jet printing system is reflected ondots recorded by the ink jet printing system; first informationgeneration means for generating first information corresponding to acontact state between dots in first dot arrangement which is the dotarrangement before the error is reflected; second information generationmeans for generating second information corresponding to a contact statebetween dots in second dot arrangement which is the dot arrangement in acase where the error is reflected; landing-interference-influenceevaluation means for calculating a landing interference evaluation valuefor quantitatively evaluating a change of the influence of dot movementdue to landing interference before and after the error is reflectedbased on the first information and the second information; and signalprocessing means for performing at least one process of a process ofgenerating a halftone parameter of a halftone processing rule or aprocess of generating a halftone image by using the landing interferenceevaluation value calculated by the landing-interference-influenceevaluation means or using an evaluation value generated based on thelanding interference evaluation value calculated by thelanding-interference-influence evaluation means.

The image processing device according to the one hundred-fifteenthaspect functions as an image processing device that performs at leastone of the process of generating the halftone processing rules whichdefine the contents of the halftone processes used in the ink jetprinting system or the halftone process. The “dots recorded by the inkjet printing system are dots of the dot image (that is, the halftoneimage) indicating the dot arrangement form on the assumption of therecording performed by the ink jet printing system. The “dots recordedby the ink jet printing system” may be all the dots constituting the dotimage, or may be some dots thereof.

The “contact state between dots” includes a state in which the dots arein contact and a state in which the dots are not in contact”.

The “before the error is reflected” refers to a state in which the erroris not reflected, that is, a case where the error is not reflected. The“case where the error is reflected” refers to a state after the error isreflected. The expression of “the error is reflected” means that theerror component is added to the dot image, and is a synonym for theaddition of the error.

The “before and after the error is reflected” refers to both the dotarrangements of the first dot arrangement which is the state before theerror is reflected and the second dot arrangement which is the stateafter the error is reflected.

The “landing interference evaluation value” is the evaluation value forquantitatively representing the degree of the change of the influence ofthe dot movement by a value. The change of the influence of the dotmovement is quantitatively evaluated by the landing interferenceevaluation value. The “evaluation value generated based on the landinginterference evaluation value” is another evaluation valuetow-dimensionally generated based on the landing interference evaluationvalue. The “evaluation value generated based on the landing interferenceevaluation value” is a value on which the landing interferenceevaluation value is reflected.

The “using the landing interference evaluation value or using theevaluation value generated based on the landing interference evaluationvalue” includes a case where a processing result of a process ofcomparing the “landing interference evaluation value” or the “evaluationvalue generated based on the landing interference evaluation value” witha certain specified value (for example, specified reference value), aprocess of comprehending an increase/decrease tendency of the “landinginterference evaluation value” or the “evaluation value generated basedon the landing interference evaluation value” by comparing the value ofthe “landing interference evaluation value” calculated from differentdot images or the “evaluation value generated based on the landinginterference evaluation value”, or a combination process thereof isused.

The halftone processing rule may be specified by the combination of thehalftone algorithm and the halftone parameter. As an example of thehalftone processing rule, there are a dither mask of the dither method,an error diffusion matrix or information of an applied gradation rangein the error diffusion method, and the number of times pixels areupdated and an exchange pixel range in the direct binary search method.

According to the one hundred-fifteenth aspect, since the change of theinfluence of the dot movement due to the landing interference before andafter the error reflection can be quantitatively evaluated using thelanding interference evaluation value, it is possible to acquire thehalftone parameter and/or the halftone image in which the change of theinfluence of the dot movement due to the landing interference before andafter the error reflection is relatively less. According to the onehundred-fifteenth aspect, it is possible to suppress the image qualitydeterioration caused by the landing interference, and it is possible togenerate an image having high image quality.

As one hundred-sixteenth aspect, in the image processing deviceaccording to the one hundred-fifteenth aspect, the signal processingmeans may generate at least one of the halftone parameter or thehalftone image having tolerance to the dot movement due to the landinginterference based on a result of a comparison process using the landinginterference evaluation value or the evaluation value generated based onthe landing interference evaluation value.

The “halftone image having tolerance to the dot movement due to thelanding interference” means that the image has robustness such that anequivalent image quality level to the landing interference phenomenon ismaintained, in other words, means that the image has fastness such thatthe image quality deterioration due to the landing interference falls inan allowable range.

As one hundred-seventeenth aspect, in the image processing deviceaccording to the one hundred-sixteenth aspect, the comparison processmay include a process of comparing the landing interference evaluationvalue with a specified reference value or a process of comparing theevaluation value generated based on the landing interference evaluationvalue with a specified reference value, and the signal processing meansmay perform at least one of a process of generating the halftoneparameter such that dot arrangement falls in an allowable rangeindicated by the specified reference value or a process of generatingthe halftone image such that dot arrangement falls in an allowable rangeindicated by the specified reference value based on the comparing resultof the comparison process.

As one hundred-eighteenth aspect, in the image processing deviceaccording to one hundred-sixteenth aspect, the signal processing meansmay generate at least one of the halftone parameter or the halftoneimage in which the degree of influence of the dot movement due to thelanding interference is equal to or less than the degree of influence ofthe dot movement indicated by the specified reference value by comparingthe landing interference evaluation value with the specified referencevalue.

As one hundred-nineteenth aspect, in the image processing deviceaccording to any one of the one hundred-fifteenth aspect to the onehundred-eighteenth aspect, the first information generation means mayinclude first analysis means for analyzing a contact direction and acontact amount of each of a plurality of dots of the first dotarrangement with another dot, the first information may be first contactstate information indicating the contact direction and the contactamount acquired by the first analysis means, the second informationgeneration means may include second analysis means for analyzing acontact state and a contact amount of each of a plurality of dots in thesecond dot arrangement with another dot, the second information may besecond contact state information indicating the contact direction andthe contact amount acquired by the second analysis means, and thelanding-interference-influence evaluation means may calculate thelanding interference evaluation value for quantitatively evaluating achange of the movement amount of the dot movement due to the landinginterference before and after the error is reflected.

As one hundred-twentieth aspect, the image processing device accordingto the one hundred-nineteenth aspect may further comprise: firstmovement amount calculation means for calculating the movement amount ofthe dot movement due to the landing interference based on the firstcontact state information; and second movement amount calculation meansfor calculating the movement amount of the dot movement due to thelanding interference based on the second contact state information. Thelanding-interference-influence evaluation means may calculate thelanding interference evaluation value based on first movement amountinformation indicating the movement amount acquired by the firstmovement amount calculation means and second movement amount informationindicating the movement amount acquired by the second movement amountcalculation means.

It is possible to directly calculate the landing interference evaluationvalue from the information of the “contact direction and the contactamount” as the first contact state information indicating the dotcontact state in the first dot arrangement and the information of the“contact direction and the contact amount” as the second contact stateinformation indicating the dot contact state in the second dotarrangement. As in the one hundred-twentieth aspect, the first movementamount information indicating the movement amount of the dot due to thelanding interference is calculated based on the information of the“contact direction and the contact amount” as the first contact stateinformation and the second movement amount information indicating themovement amount of the dot due to the landing interference is calculatedbased on the information of the “contact direction and the contactamount” as the second contact state information, so that the landinginterference evaluation value may be calculated from the first movementamount information and the second movement amount information. It isunderstood that the landing interference evaluation value calculated bythe configuration of the one hundred-twentieth aspect is calculatedbased on the first contact state information and the second contactstate information.

As one hundred-twenty-first aspect, in the image processing deviceaccording to the one hundred-nineteenth aspect or the onehundred-twentieth aspect, the landing-interference-influence evaluationmeans may calculate the landing interference evaluation value forquantitatively evaluating a change of the movement amount of only a dotgroup to which the error is reflected.

According to the one hundred-twenty-first aspect, it is possible toreduce the calculation amount, and it is possible to simply evaluate theinfluence of the landing interference.

As one hundred-twenty-second aspect, in the image processing deviceaccording to any one of the one hundred-nineteenth aspect to the onehundred-twenty-first aspect, in a case where the dot forming positionshift is reflected as the error, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefor quantitatively evaluating only a change of the movement amount in adirection parallel to a direction to which the error due to the dotforming position shift is applied, among directions of the dot movementdue to the landing interference.

As one hundred-twenty-third aspect, in the image processing deviceaccording to any one of the one hundred-nineteenth aspect to the onehundred-twenty-second aspect, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefor quantitatively evaluating only a change of the movement amount in adirection perpendicular to a scanning direction of the ink jet printingsystem, among directions of the dot movement due to the landinginterference.

As one hundred-twenty-fourth aspect, in the image processing deviceaccording to any one of the one hundred-fifteenth aspect to the onehundred-eighteenth aspect, the first information may be first contactstate information indicating a contact state between dots in the firstdot arrangement, the second information may be second contact stateinformation indicating a contact state between dots in the second dotarrangement, and the landing-interference-influence evaluation means maycalculate the landing interference evaluation value for quantitativelyevaluating a change of the contact state before and after the error isreflected.

As one hundred-twenty-fifth aspect, in the image processing deviceaccording to the one hundred-twenty-fourth aspect, the change of thecontact state may be represented by any one of a first state changechanged from a contact state of a dot with another dot to a non-contactstate and a second state change changed from the non-contact state ofthe dot with the other dot to the contact state, or the number of dotsexhibiting both the state changes of the first state change and thesecond state change.

As one hundred-twenty-sixth aspect, in the image processing deviceaccording to the one hundred-twenty-fourth aspect to the onehundred-twenty-fifth aspect, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefor quantitatively evaluating a change of the contact state of only adot group on which the error is reflected.

According to the one hundred-twenty-sixth aspect, it is possible toreduce the calculation amount, and it is possible to simply evaluate theinfluence of the landing interference.

As one hundred-twenty-seventh aspect, in the image processing deviceaccording to any one of the one hundred-twenty-fourth aspect to the onehundred-twenty-sixth aspect, in a case where the dot forming positionshift is reflected as the error, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefor quantitatively evaluating only a change of the contact state in adirection parallel to a direction to which the error due to the dotforming position shift is added, among directions of the dot movementdue to the landing interference.

As one hundred-twenty-eighth aspect, in the image processing deviceaccording to any one of the one hundred-twenty-fourth aspect to the onehundred-twenty-seventh aspect, the landing-interference-influenceevaluation means may calculate the landing interference evaluation valuefor quantitatively evaluating only a change of the contact state in adirection perpendicular to a scanning direction of the ink jet printingsystem, among directions of the dot movement due to the landinginterference.

An ink jet printing system according to one hundred-twenty-ninth aspectis an ink jet printing system comprising: the image processing deviceaccording to any one of the one hundred-fifteenth aspect to the onehundred-twenty-eighth aspect; and an ink jet printing device thatperforms printing on a printing medium based on a halftone imagegenerated through a halftone process determined by the halftoneprocessing rule or a halftone image generated by the signal processingmeans.

An image processing method according to one hundred-thirtieth aspect isan image processing method comprising: an error reflection processingstep of generating the dot arrangement in which at least one error of adot diameter, a dot shape, a dot forming position shift, or non-jettingwhich is an element of an error of an ink jet printing system isreflected on dots recorded by the ink jet printing system; a firstinformation generation step of generating first informationcorresponding to a contact state between dots in first dot arrangementwhich is the dot arrangement before the error is reflected; a secondinformation generation step of generating second informationcorresponding to a contact state between dots in second dot arrangementwhich is the dot arrangement in a case where the error is reflected; alanding-interference-influence evaluation step of calculating a landinginterference evaluation value for quantitatively evaluating a change ofthe influence of the dot movement due to the landing interference beforeand after the error is reflected based on the first information and thesecond information; and a signal processing step of performing at leastone process of a process of generating a halftone parameter of ahalftone processing rule or a process of generating a halftone image byusing the landing interference evaluation value calculated in thelanding-interference-influence evaluation step or using an evaluationvalue generated based on the landing interference evaluation valuecalculated in the landing-interference-influence evaluation step.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-sixteenth aspect to the onehundred-twenty-eighth aspect with the one hundred-thirtieth aspect. Inthis case, means serving as the process or function specified in theimage processing device may be comprehended as an element of a “step” ofa corresponding process or operation.

The image processing method according to the one hundred-sixteenthaspect in a case where the signal processing step performs the processof generating the halftone parameter of the halftone processing rule maybe comprehended as the invention of the method of generating thehalftone processing rule. The halftone processing rule may becomprehended as information provided for the halftone process and isequivalent to a program. Accordingly, the image processing methodaccording to the one hundred-thirtieth aspect in a case where the signalprocessing step of generating the halftone parameters is provided may beinterpreted as the method of producing the halftone processing rule.

The image processing method according to the one hundred-thirtiethaspect in a case where the signal processing step performs the halftoneprocess of generating the halftone image may be comprehended as theinvention of the halftone processing method, or may be comprehended asthe invention of the method of generating the halftone image. Thehalftone image may be a form of image data as information provided forthe printing control process, or may be a form of the print imageprinted according to the image data. The image processing methodaccording to the one hundred-thirtieth aspect in a case where the signalprocessing step of generating the halftone image is provided may beinterpreted as the invention of the method of producing the halftoneimage.

A program according to one hundred-thirty-first aspect is a programcausing a computer to function as: error reflection processing means forgenerating the dot arrangement in which at least one error of a dotdiameter, a dot shape, a dot forming position shift, or non-jettingwhich is an element of an error of an ink jet printing system isreflected on dots recorded by the ink jet printing system; firstinformation generation means for generating first informationcorresponding to a contact state between dots in first dot arrangementwhich is the dot arrangement before the error is reflected; secondinformation generation means for generating second informationcorresponding to a contact state between dots in second dot arrangementwhich is the dot arrangement in a case where the error is reflected;landing-interference-influence evaluation means for calculating alanding interference evaluation value for quantitatively evaluating achange of the influence of the dot movement due to the landinginterference before and after the error is reflected based on the firstinformation and the second information; and signal processing means forperforming at least one process of a process of generating a halftoneparameter of a halftone processing rule or a process of generating ahalftone image by using the landing interference evaluation valuecalculated by the landing-interference-influence evaluation means orusing an evaluation value generated based on the landing interferenceevaluation value calculated by the landing-interference-influenceevaluation means.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-sixteenth aspect to the onehundred-twenty-eighth aspect to the one hundred-thirty-first aspect. Inthis case, means serving as the process or function specified in theimage processing device may be comprehended as an element of a programfor realizing means of a corresponding process or operation.

An image processing device according to one hundred-thirty-second aspectis an image processing device comprising: analysis means for analyzing acontact state of each dot of a plurality of pixels recorded by an inkjet printing system with another dot; group classification means forperforming a group classification process of classifying dots into aplurality of groups based on information indicating the contact stateacquired by the analysis means; dispersibility-evaluation-valuecalculation means for calculating a dispersibility evaluation value forevaluating dispersibility of a dot group for each classified group; andsignal processing means for performing at least one process of a processof generating a halftone parameter of a halftone processing rule or aprocess of generating a halftone image by using the dispersibilityevaluation value calculated by the dispersibility-evaluation-valuecalculation means or using an evaluation value generated based on thedispersibility evaluation value calculated by thedispersibility-evaluation-value calculation means.

The image processing device according to the one hundred-thirty-secondaspect functions as an image processing device that performs at leastone of the process of generating the halftone processing rules whichdefine the contents of the halftone processes used in the ink jetprinting system or the halftone process. The “dots recorded by the inkjet printing system are dots of the dot image (that is, the halftoneimage) indicating the dot arrangement form on the assumption of therecording performed by the ink jet printing system. The “dots recordedby the ink jet printing system” may be all the dots constituting the dotimage, or may be some dots thereof.

Here, the “contact state” refers to the contact direction and/or thecontact amount. The movement direction and the movement amount of thedot movement due to the landing interference may be different dependingon the contact state between the dots, the movement direction or themovement amount due to the landing interference may be estimated fromthe contact state. Accordingly, it is possible to classify the dots interms of the influence of the landing interference based on theinformation indicating the contact state. Here, the “influence due tothe landing interference” includes the combination of the movementdirection and the movement amount of the dot movement due to the landinginterference.

The dot group having the common or similar contact state may beestimated that the influence due to the landing interference is incommon or is similar, and the dot group having the common or similarcontact state may be classified as the same group. Here, the “similar”means that the dots have similarity falling in an allowable rangecapable of being treated as a substantially same range depending on thedetailedness of the classification. The dots may be classified into aplurality of groups depending on different contact states. In a casewhere the dots are classified into the groups in consideration of only aspecific contact state, it is interpreted that the dots are classifiedinto at least two groups of the group of the dot group corresponding tothe considered specific contact state or the non-corresponding group.

The “for each classified group” is not limited to each of all theclassified groups, and includes the meaning of a per group basis of atleast one group which is a part of the plurality of classified groups.The dispersibility-evaluation-value calculation means calculates thedispersibility evaluation value for evaluating dispersibility of the dotgroup on a per group basis for all the plurality of classified groups ora part of the groups. A case where the dispersibility evaluation valueis calculated for only one (single) group of the plurality of classifiedgroups is included in the concept of the “each classified group”.

The “dispersibility evaluation value” is an evaluation value forquantitatively representing the dispersibility of the dot group by thevalue. The degree of the influence of the dot movement due to thelanding interference is quantitatively evaluated by the dispersibilityevaluation value for each classified group. The dispersibilityevaluation value may be used as the landing interference evaluationvalue for evaluating the influence of the landing interference.

The “evaluation value generated based on the dispersibility evaluationvalue” is another evaluation value two-dimensionally generated based onthe dispersibility evaluation value. The “evaluation value generatedbased on the dispersibility evaluation value” is a value on which thedispersibility evaluation value is reflected.

The “using the dispersibility evaluation value or using the evaluationvalue generated based on the dispersibility evaluation value” includes acase where a processing result of a process of comparing the“dispersibility evaluation value” or the “evaluation value generatedbased on the dispersibility evaluation value” with a certain specifiedvalue (for example, specified reference value), a process ofcomprehending an increase/decrease tendency of the “dispersibilityevaluation value” or the “evaluation value generated based on thedispersibility evaluation value” by comparing the value of the“dispersibility evaluation value” calculated from different dot imagesor the “evaluation value generated based on the dispersibilityevaluation value”, or a combination process thereof is used.

The halftone processing rule may be specified by the combination of thehalftone algorithm and the halftone parameter. As an example of thehalftone processing rule, there are a dither mask of the dither method,an error diffusion matrix or information of an applied gradation rangein the error diffusion method, and the number of times pixels areupdated and an exchange pixel range in the direct binary search method.

According to the one hundred-thirty-second aspect, it is possible toevaluate the dispersibility of each dot group for each group of the dotgroup in which the influence of the landing interference is in common oris similar, and it is possible to acquire the halftone parameter and/orthe halftone image in which the dispersibility of each dot group isfavorable. According to the one hundred-thirty-second aspect, it ispossible to suppress the image quality deterioration caused by thelanding interference, and it is possible to generate the image havinghigh image quality.

As one hundred-thirty-third aspect, in the image processing deviceaccording to the one hundred-thirty-second aspect, the signal processingmeans may generate at least one of the halftone parameter or thehalftone image having tolerance to dot movement due to landinginterference based on a result of a comparison process using thedispersibility evaluation value or the evaluation value generated basedon the dispersibility evaluation value.

As one hundred-thirty-fourth aspect, in the image processing deviceaccording to the one hundred-thirty-third aspect, the comparison processmay include a process of comparing the dispersibility evaluation valuewith a specified reference value or a process of comparing theevaluation value generated based on the dispersibility evaluation valuewith a specified reference value, and the signal processing means mayperform at least one of a process of generating the halftone parametersuch that dot arrangement falls in an allowable range indicated by thespecified reference value or a process of generating the halftone imagesuch that dot arrangement falls in an allowable range indicated by thespecified reference value based on the comparing result of thecomparison process.

The “specified reference value” may be appropriately set in terms of anallowable range of the dispersibility evaluation value or an allowablerange of the target image quality. The reference value compared with thedispersibility evaluation value and the reference value compared withthe evaluation value generated based on the dispersibility evaluationvalue may be set to be different reference values.

As one hundred-thirty-fifth aspect, in the image processing deviceaccording to the one hundred-thirty-third aspect, the signal processingmeans may generate at least one of the halftone image or the halftoneparameter in which the dot group has a favorable dispersibility equal toor greater than a reference of the dispersibility indicated by thereference value by comparing the dispersibility evaluation value withthe specified reference value.

As one hundred-thirty-sixth aspect, the image processing deviceaccording to any one of the one hundred-thirty-second aspect to the onehundred-thirty-fifth aspect may further comprise: movement amountcalculation means for calculating a movement direction and a movementamount of dot movement due to landing interference based on informationindicating the contact state acquired by the analysis means. The groupclassification means may perform the group classification process basedon information indicating the movement direction and the movement amountacquired by the movement amount calculation means.

It is possible to directly perform the group classification process fromthe information indicating the contact state. As in the onehundred-thirty-sixth aspect, the movement direction and the movementamount of the dot movement due to the landing interference is calculatedbased on the information indicating the contact state, and the groupclassification process may be performed from the information indicatingthe movement direction and the movement amount.

As one hundred-thirty-seventh aspect, the image processing deviceaccording to any one of the one hundred-thirty-second aspect to the onehundred-thirty-sixth aspect may further comprise: error reflectionprocessing means for generating the dot arrangement in which at leastone error of a dot diameter, a dot shape, a dot forming position shift,or non-jetting which is an element of an error of the ink jet printingsystem is reflected. The group classification means may perform thegroup classification process based on the information indicating thecontact state of the dot on which the error is reflected.

As one hundred-thirty-eighth aspect, in the image processing deviceaccording to the one hundred-thirty-seventh aspect, the groupclassification means may perform the group classification process ononly a dot group on which the error is reflected.

According to the one hundred-thirty-eighth aspect, it is possible toreduce a calculation amount, and it is possible to simply evaluate theinfluence of the landing interference.

As one hundred-thirty-ninth aspect, in the image processing deviceaccording to the one hundred-thirty-seventh aspect to the onehundred-thirty-eighth aspect, in a case where the dot forming positionshift is reflected as the error, the group classification means mayperform the group classification process on only dots in which amovement direction of the dot movement due to the landing interferenceis a direction parallel to a direction to which the error is added.

As one hundred-fortieth aspect, in the image processing device accordingto any one of the one hundred-thirty-seventh aspect to the onehundred-thirty-ninth aspect, in a case where the dot forming positionshift is reflected as the error, the dispersibility-evaluation-valuecalculation means may calculate the dispersibility evaluation value foronly a group to which the dots in which the movement direction of thedot movement due to the landing interference is the direction parallelto the direction to which the error is added belong.

An ink jet printing system according to one hundred-forty-first aspectis an ink jet printing system comprising: the image processing deviceaccording to any one of the one hundred-thirty-second aspect to the onehundred-fortieth aspect; and an ink jet printing device that performsprinting on a printing medium based on a halftone image generatedthrough a halftone process determined by the halftone processing rule ora halftone image generated by the signal processing means.

An image processing method according to one hundred-forty-second aspectis an image processing method comprising: an analysis step of analyzinga contact state of each dot of a plurality of pixels recorded by an inkjet printing system with another dot; a group classification step ofperforming a group classification process of classifying dots into aplurality of groups based on information indicating the contact stateacquired in the analysis step; a dispersibility-evaluation-valuecalculation step of calculating a dispersibility evaluation value forevaluating dispersibility of each dot group for each classified group;and a signal processing step of performing at least one process of aprocess of generating a halftone parameter of a halftone processing ruleor a process of generating a halftone image by using the dispersibilityevaluation value calculated in the dispersibility-evaluation-valuecalculation step or using an evaluation value generated based on thedispersibility evaluation value calculated in thedispersibility-evaluation-value calculation step.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-thirty-third aspect to the onehundred-fortieth aspect with the one hundred-forty-second aspect. Inthis case, means serving as the process or function specified in theimage processing device may be comprehended as an element of a “step” ofa corresponding process or operation.

The image processing method according to the one hundred-forty-secondaspect in a case where the image processing step performs the process ofgenerating the halftone parameter of the halftone processing rule may becomprehended as the invention of the method of producing the halftoneprocessing rule. The halftone processing rule is information providedfor the halftone process and is equivalent to a program. Accordingly,the image processing method according to the one hundred-forty-secondaspect in a case where the signal processing step of generating thehalftone parameter is provided may be interpreted as the invention ofthe method of generating the halftone processing rule.

The image processing method according to the one hundred-forty-secondaspect in a case where the signal processing step performs the halftoneprocess of generating the halftone image may be comprehended as theinvention of the halftone processing method, or may be comprehended asthe invention of the method of generating the halftone image. The“halftone image” may be a form of image data as information provided forthe printing control process, or may be a form of the print imageprinted according to the image data. The image processing methodaccording to the one hundred-forty-second aspect in a case where thesignal processing step of generating the halftone image is provided maybe interpreted as the invention of the method of producing the halftoneimage.

A program according to one hundred-forty-third aspect is a programcausing a computer to function as: analysis means for analyzing acontact state of each dot of a plurality of pixels recorded by an inkjet printing system with another dot; group classification means forperforming a group classification process of classifying dots into aplurality of groups based on information indicating the contact stateacquired by the analysis process; dispersibility-evaluation-valuecalculation means for calculating a dispersibility evaluation value forevaluating dispersibility of each dot group for each classified group;and signal processing means for performing at least one process of aprocess of generating a halftone parameter of a halftone processing ruleor a process of generating a halftone image by using the dispersibilityevaluation value calculated by the dispersibility-evaluation-valuecalculation means or using an evaluation value generated based on thedispersibility evaluation value calculated by thedispersibility-evaluation-value calculation means.

It is possible to appropriately combine the same matters as the mattersspecified in the one hundred-thirty-third aspect to the onehundred-fortieth aspect with the one hundred-forty-third aspect. In thiscase, means serving as the process or function specified in the imageprocessing device may be comprehended as an element of a program forrealizing means of a corresponding process or operation.

According to the inventions described in the first aspect to thefifty-fourth aspect, it is possible to set the characteristic parametersrelated to the characteristics of the printing system without giving anexcessive load to a user, and it is possible to generate the halftoneprocessing rule appropriate for the printing system.

According to the inventions described in the fifty-fifth aspect to thesixty-fifth aspect, since the output condition of the characteristicparameter acquisition chart including the pattern for acquiring thecharacteristic parameter is set depending on the set printing mode, itis possible to output the characteristic parameter acquisition chart onwhich the characteristics of the printing system for each printing modeare reflected, and it is possible to appropriately comprehend thecharacteristics of the printing system for each printing mode.

According to the inventions described in the sixty-sixth aspect to theninety-ninth aspect, the appropriate halftone processing rule isgenerated based on the simulation image in which the system error on theassumption of actual printing is reflected. Accordingly, it is possibleto acquire the image having favorable image quality.

According to the inventions described in the one hundredth aspect to theone hundred-forty-third aspect, it is possible to generate the halftoneprocessing rule or perform the halftone process capable of suppressingthe image quality deterioration caused by the landing interference.Accordingly, it is possible to acquire the image having tolerance to thelanding interference and favorable image quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration example of a printingsystem according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration example of animage processing device.

FIG. 3 is a block diagram for describing a function of an imageprocessing device according to a first embodiment.

FIG. 4 is a flowchart showing an example of a method of generating ahalftone processing rule.

FIG. 5 is a diagram showing an example of a characteristic parameteracquisition chart.

FIG. 6 is a schematic plan view of a serial scan type ink jet printingdevice used to draw the characteristic parameter acquisition chart ofFIG. 5.

FIG. 7 is an explanatory diagram of a characteristic parameter relatedto landing interference.

FIG. 8 is a diagram showing a landing interference parameter expressedby a function of an inter-dot distance.

FIG. 9 is a table showing the advantages and disadvantages of varioushalftone algorithms for a plurality of requirements.

FIG. 10 is a flowchart related to a process of generating a halftoneparameter.

FIG. 11 is a conceptual diagram of the simulation image.

FIG. 12A shows that the jetting order in a drawing mode in which drawingis performed along 8 scanning paths is represented by a path number.

FIG. 12B is a conceptual diagram in a case where a predetermined amountof error is added to dots of pixels of a first path in a case where thedrawing is performed in the drawing mode shown in FIG. 12A.

FIG. 13 is an explanatory diagram showing that the error in which a dotdiameter is decreased by a predetermined amount is added to dots ofpixels of a third path in a case where the drawing is performed in thedrawing mode shown in FIG. 12A.

FIG. 14 is a flowchart of an example in which a dither mask is generatedusing a void-and-cluster method.

FIG. 15 is a schematic diagram showing an example of a halftoneselection chart.

FIG. 16 is a flowchart showing a procedure of generating a halftoneimage of the halftone selection chart using a DBS method.

FIG. 17 is a graph showing qualitative tendencies of various halftoneprocessing rules.

FIG. 18 is a graph showing the relationship between tolerance toinstability of the system and granularity.

FIG. 19 is a block diagram for describing a function of an imageprocessing device according to a second embodiment.

FIG. 20 is a flowchart showing another example of a method of generatingthe halftone processing rule.

FIG. 21 is a diagram showing another example of the characteristicparameter acquisition chart.

FIG. 22 is a schematic plan view of a single path type inkjet printingdevice used in the drawing of the characteristic parameter acquisitionchart of FIG. 21.

FIG. 23 is a schematic diagram showing an example of a chart formeasuring a head vibration error according to carriage movement.

FIG. 24 is an explanatory diagram showing a shift amount of a recordingposition.

FIG. 25A is a graph showing an example of a head vibration error, and isa graph showing a position shift amount in a main scanning direction.

FIG. 25B is a graph showing an example of a head vibration error, and isa graph showing a position shift amount in a sub scanning direction.

FIG. 26 is a schematic diagram showing an example of a chart formeasuring a paper transport error.

FIG. 27 is a distribution diagram showing an example of the distributionof the measurement values of the paper transport error.

FIG. 28 is a schematic diagram showing an example for acquiring a headvibration error parameter in the single path type.

FIG. 29 is a schematic diagram showing an example of a chart foracquiring a head module attachment error parameter.

FIG. 30A is a schematic diagram for describing a shift of a centralposition of gravity of a dot array.

FIG. 30B is an explanatory diagram of an inclination angle of the dotarray.

FIG. 31 is a graph showing the relationship between a system errordistribution and a level of a random system error reflected on thegeneration of the simulation image.

FIG. 32 is an explanatory diagram for describing the relationshipbetween levels of a plurality of random system errors and a weightingfactor.

FIG. 33 is a diagram showing that a two-dimensional error distributionin the main scanning direction and the sub scanning direction isrepresented as shades.

FIG. 34 is a sectional view of the error distribution along the mainscanning direction in the two-dimensional error distribution shown inFIG. 33.

FIG. 35 is a sectional view of the error distribution along the subscanning direction in the two-dimensional error distribution shown inFIG. 33.

FIG. 36 is a block diagram showing major parts of an image processingdevice according to a third embodiment.

FIG. 37 is a block diagram showing the configuration of a printingsystem according to a fourth embodiment.

FIG. 38 is a flowchart of a method of generating a halftone processingrule to which the updating of the characteristic parameter according tothe fourth embodiment is applied.

FIG. 39 is an explanatory diagram of an example of the updating of thecharacteristic parameter in a case where the system error is applied toa specified value.

FIG. 40 is an explanatory diagram of a difference between an existingchange amount of an inter-dot distance and a new change amount of aninter-dot distance.

FIG. 41 is a flowchart of a method of generating a halftone processingrule applied to a modification example of the printing system accordingto the fourth embodiment.

FIG. 42 is a flowchart of a method of generating a halftone processingrule according to a fifth embodiment.

FIG. 43A is a conceptual diagram of the method of generating a halftoneprocessing rule according to the fifth embodiment.

FIG. 43B is a conceptual diagram of a method of generating a halftoneprocessing rule according to an application example of the fifthembodiment.

FIG. 44 is a flowchart of the method of generating a halftone processingrule according to the application example of the fifth embodiment.

FIG. 45 is a flowchart of a first modification example of the method ofgenerating a halftone processing rule according to the applicationexample of the fifth embodiment.

FIG. 46 is a flowchart of a second modification example of the method ofgenerating a halftone processing rule according to the applicationexample of the fifth embodiment.

FIG. 47 is a block diagram showing the configuration of an imageprocessing device applied to a printing system according to a sixthembodiment.

FIG. 48 is a block diagram showing the configuration of an imageprocessing device applied to a printing system according to a seventhembodiment.

FIG. 49 is an explanatory diagram of a printing mode.

FIG. 50 is a flowchart of a method of acquiring a characteristicparameter according to the seventh embodiment.

FIG. 51 is a flowchart of a method of acquiring a characteristicparameter according to a modification example of the seventh embodiment.

FIG. 52 is a flowchart according to an eighth embodiment showing anotherexample of the method of generating a halftone processing rule shown inFIG. 4.

FIG. 53 is an explanatory diagram showing an example of an input screenused in an input step of the flowchart shown in FIG. 52.

FIG. 54 is an explanatory diagram showing another example of a dot shapeitem on the input screen shown in FIG. 53.

FIG. 55 is a flowchart of an aspect (ninth embodiment) in which theinfluence of the landing interference when the simulation image shown inFIG. 11 is generated is reflected.

FIG. 56 is a conceptual diagram in which the jetting order of a drawingmode in which drawing is performed along 8 scanning paths is denoted bya path number.

FIG. 57 is a conceptual diagram of a simulation image showing thearrangement of dots jetted along a first path in the generation of thesimulation image.

FIG. 58A is a conceptual diagram of a simulation image showing thearrangement of dots jetted up to a second path in the generation of thesimulation image.

FIG. 58B is a conceptual diagram of a simulation image showing the dotarrangement in which the dots are rearranged by reflecting the influenceof the landing interference.

FIG. 59A is a conceptual diagram of a simulation image showing thearrangement of dots jetted up to a third path in the generation of thesimulation image.

FIG. 59B is a conceptual diagram of a simulation image showing the dotarrangement in which the dots are rearranged by reflecting the influenceof the landing interference.

FIG. 60 is an explanatory diagram of the inter-dot distance.

FIG. 61 is an explanatory diagram of the function used in Expression(11) to Expression (14).

FIG. 62A is a conceptual diagram showing a change due to the landinginterference including a dot shape, and is a diagram showing therelationship between an inter-density-maximum-point distance and aninter-center distance of two dots in a case where the landinginterference does not occur.

FIG. 62B is a conceptual diagram showing a change due to the landinginterference including a dot shape, and is a diagram showing therelationship between an inter-density-maximum-point distance and aninter-center distance of two dots in a case where the landinginterference occurs.

FIG. 63 is a schematic diagram of the dot when the dot of FIG. 62B isviewed from the top.

FIG. 64 is a flowchart related to the process of generating the halftoneparameter as an example of means for suppressing image qualitydeterioration due to the landing interference.

FIG. 65 is a flowchart showing an example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

FIG. 66 is an explanatory diagram for describing a method of calculatinga movement direction and a movement amount of dot movement due to thelanding interference.

FIG. 67 is an explanatory diagram showing an example of the dotarrangement on which an error due to a dot forming position shift of aspecific nozzle of a recording head is reflected.

FIG. 68 is a block diagram of major parts for describing the function ofan image processing device according to a tenth embodiment.

FIG. 69 is a flowchart in a case where the void-and-cluster method isused at the time of halftone design in the dither method as an exampleof means for suppressing image quality deterioration due to the landinginterference.

FIG. 70 is a flowchart showing an example of the more detailedprocessing contents of step S523 and step S524 of FIG. 69.

FIG. 71 is a flowchart in a case where the halftone process using theDBS method as an example of means for suppressing image qualitydeterioration due to the landing interference is performed.

FIG. 72 is a flowchart showing an example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71.

FIG. 73 is an explanatory diagram in a case where a landing interferenceevaluation value is acquired from a contact direction and a contactamount of a dot.

FIG. 74 is a flowchart showing another example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

FIG. 75 is an explanatory diagram for describing a method of calculatingchanges of the movement direction and the movement amount before andafter the error of the dot forming position shift shown in FIGS. 66 and67 is reflected.

FIG. 76 is a block diagram of major parts for describing the function ofan image processing device according to an eleventh embodiment.

FIG. 77 is a flowchart showing another example of the more detailedprocessing content of step S523 and step S524 of FIG. 69.

FIG. 78 is a flowchart showing another example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71.

FIG. 79 is a flowchart according to another embodiment capable of beingapplied instead of the flowchart of FIG. 74.

FIG. 80A is an explanatory diagram related to a change of the contactstate, and is a diagram showing an example of a dot image before theerror reflection.

FIG. 80B is an explanatory diagram related to a change of the contactstate, and is a diagram showing an example of a dot image after theerror reflection.

FIG. 81A is an explanatory diagram related to a change of the contactstate, and is a diagram showing an example of a dot image before theerror reflection.

FIG. 81B is an explanatory diagram related to a change of the contactstate, and is a diagram showing an example of a dot image after theerror reflection.

FIG. 82 is a block diagram of major parts for describing the function ofan image processing device according to a twelfth embodiment.

FIG. 83 is a flowchart according to another embodiment capable of beingapplied instead of the flowchart of FIG. 77.

FIG. 84 is a flowchart according to another embodiment capable of beingapplied instead of the flowchart of FIG. 78.

FIG. 85 is a flowchart showing another example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

FIG. 86 is a block diagram of major parts for describing the function ofan image processing device according to a thirteenth embodiment.

FIG. 87 is a flowchart showing another example of the more detailedprocessing contents of step S523 and step S524 of FIG. 69.

FIG. 88 is a flowchart showing another example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71.

FIG. 89 is a block diagram of major parts for describing the function ofan image processing device according to a fourteenth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration example of a printingsystem according to an embodiment of the present invention. A printingsystem 10 includes a desk top publishing device (DTP) 12, a databaseserver 14, a management computer 16, an image processing device 20, aprinting control device 22, a printing device 24, and an image readingdevice 26. The image processing device 20 is connected to the DTP device12, the database server 14, the management computer 16, the printingcontrol device 22 and the image reading device 26 via an electriccommunication line 28.

The electric communication line 28 may be a local area network (LAN), awide area network (WAN), or may be a combination thereof. The electriccommunication line 28 is not limited to a wired communication line, anda part of the electric communication line or the entire electriccommunication line may be a wireless communication line. In the presentspecification, the term “connection” between devices capable ofdelivering a signal is not limited to a wired connection, and includes awireless connection.

The DTP device 12 is a device that generates manuscript image dataindicating the content of an image desired to be printed. The DTP device12 is realized by combining hardware and software of a computer. Theterm “software” is a synonym for a program. The DTP device 12 is used toperform an operation of editing various kinds of image components suchas characters, figures, patterns, illustrations and photographic imageswhich are desired to be printed and laying the image components out on aprinting surface.

The manuscript image data as print source image data is generated by theediting operation performed by the DTP device 12. The DTP device 12generates an electronic manuscript using a page description language(PDL). The manuscript image data generated by the DTP device 12 istransmitted to the database server 14 or the image processing device 20.Means for generating the manuscript image data is not limited to anaspect in which the manuscript image data is generated by the DTP device12, and may include an aspect in which the manuscript image data isgenerated by another computer or an image creating and editing device(not shown). The manuscript image data may be input to the databaseserver 14, the image processing device 20, or the printing controldevice 22 via the electric communication line 28 or using a removalmedia (external storage medium) such as a memory card.

The database server 14 is a device that manages various data items suchas a job ticket of the electronic manuscript, color sample data, targetprofile, and device profile appropriate for a combination of theprinting device 24 and paper. For example, the job ticket may be in theform of a job definition format (JDF) file.

The management computer 16 performs various managements in the printingsystem 10. For example, the management computer performs an imagemanagement, a printing job management, and an operation statusmanagement of one or plurality of printing devices 24.

The image processing device 20 functions as means for performingrasterizing on the printing manuscript image data (for example, datadescribed using a page description language) generated by the DTP device12. The rasterizing process is called a raster image processor (RIP)process. The image processing device 20 may realize one function of aRIP device.

The image processing device 20 has a halftone processing function and acolor conversion function of converting the printing manuscript imagedata which is a continuous-tone image into each color dot-patterned dataappropriate for the output of the printing device 24. The imageprocessing device 20 of the present example has a function of generatingtwo or more halftone processing rules for the halftone processingfunction, based on characteristic parameter of the printing device 24 ofthe printing system 10. That is, the image processing device 20 has ahalftone process generation function of generating the halftoneprocessing rule and a halftone processing function of performing thehalftone process on the continuous-tone image using the generatedhalftone processing rules. The image processing device 20 may berealized by combining the hardware and the software of the computer.

The halftone processing rule is a processing rule for performing thehalftone process of converting data of the continuous-tone image intodata of a halftone image which is the dot-patterned data. The halftoneprocessing rule is defined by a combination of a halftone algorithm anda halftone parameter. The halftone processing rule means a specificcalculation mechanism of the halftone process, and specifies the contentof the halftone process.

For example, as the kind of the halftone algorithm, there are a dithermethod, an error diffusion method, and a direct binary search method.The halftone parameter is a specific parameter used in a calculationprocess according to the halftone algorithm. The halftone parameter isdetermined for each halftone algorithm. For example, as the halftoneparameter in the dither method, a size and a threshold value of a dithermatrix are determined. As the halftone parameter in the error diffusionmethod, there are a matrix size of an error diffusion matrix, an errordiffusion coefficient, and setting of an applied gradation section ofeach error diffusion matrix. As the halftone parameter in the directbinary search method, there are a pixel update number indicating thenumber of times a process of replacing (exchanging) pixels is performed,and an exchange pixel range indicating a pixel range in which the pixelsare replaced. A parameter for evaluating tolerance to a system error maybe added to the halftone parameter in each halftone algorithm. When thehalftone processing rule is generated, at least one parameter of theplurality of parameters described above is specified as the halftoneparameter.

The specific content of the processing function of the image processingdevice 20 will be described below. The data of the halftone imagegenerated by the image processing device 20 is supplied to the printingcontrol device 22, and thus, a target image is printed by the printingdevice 24.

The printing control device 22 controls a printing operation performedthe printing device 24 based on the print image data generated by theimage processing device 20. The printing device 24 is image formingmeans for printing the image data according to the control of theprinting control device 22. A printing method or the kind of colormaterial to be used in the printing device 24 is not particularlylimited. For example, as the printing device 24, various kinds ofprinting devices such as an ink jet printing machine, anelectrophotographic printer, a laser printer, an offset printing machineand a flexographic printing machine may be adopted. The term “printingdevice” is understood as a synonym for a printing machine, a printer, animage recording device, an image forming device and an image outputdevice. As the color material, ink or toner may be used depending on thekind of the printing device 24.

Here, an example in which an ink jet printing machine which is anexample of a non-plate type digital printing machine is used as theprinting device 24 will be described. In the printing system 10according to the present embodiment, an ink jet printing machine capableof forming a color image using four color inks of cyan (C), magenta (M),yellow (Y) and black (K) is used as an example of the printing device24. However, the number of colors of the inks or a combination thereofis not limited to this example. For example, in addition to four colorsof CMYK, an aspect in which light color inks such as light cyan (LC) andlight magenta (LM) are added, or an aspect in which special color inkssuch as red and green are used may be applied.

Although an aspect in which the printing control device 22 and theprinting device 24 are depicted as separate blocks and a signal isdelivered between these devices through the wired or wirelesscommunication connection has been shown in FIG. 1, the presentembodiment is not limited to such a configuration, and a printing devicein which the printing control device 22 and the printing device 24 areintegrally combined may be used.

In a case where a plate type printing machine using a printing plate isadopted as the printing device 24, the printing system includes a platemaking device (not shown) such as a plate recorder that makes a printingplate from the image data in addition to the printing control device 22.In this case, the plate making device such as the plate recorder, acontroller thereof, and a printing machine that prints the image datausing the printing plate made by the plate making device are connectedto the electric communication line 28. In a case where the plate typeprinting machine is used, the configuration in which the printingcontrol device 22, the plate making device (not shown) and the printingdevice 24 are combined can be comprehended as the “printing device” as awhole. The printing device 24 corresponds to one example of an “imageforming unit”.

The image reading device 26 is means for reading an image of a printedmaterial printed by the printing device 24 and generating electronicimage data indicating the read image. The image reading device 26includes an imaging element (photoelectric conversion element) thatimages the image of the printed material and converts the imaged imageinformation into an electric signal, and a signal processing circuitthat processes the signal acquired from the image element and generatesdigital image data.

As the image reading device 26, a separate scanner (for example, aflatbed scanner, that is, an office scanner capable of being usedonline) from the printing device 24 may be used. The image readingdevice 26 may be combined with the printing device 24. For example, linesensors (image units) for reading the image may be provided in a papertransport path of the printing device 24, and a print image may be readby the line sensors while transporting the printed material on which theimage has formed. The line sensor for reading the image which isprovided in the paper transport path in the printing device 24 isreferred to as the term “inline scanner” or “inline sensor” in somecases. The image reading device 26 corresponds to one example of “imagereading means”.

The read image data of the print image generated by the image readingdevice 26 is input to the image processing device 20. The imageprocessing device 20 has a function of analyzing the read image dataacquired from the image reading device 26.

<Variation of System Configuration>

The functions of the DTP device 12, the database server 14, themanagement computer 16, the image processing device 20 and the printingcontrol device 22 may be realized by one computer, or may be realized bya plurality of computers. The roles and functions of the respectivecomputers may be shared in various forms. For example, the functions ofthe DTP device 12 and the image processing device 20 may be realized byone computer, or the function of the image processing device 20 may beoffered within the management computer 16. The function of the imageprocessing device 20 and the function of the printing control device 22may be realized by one computer. The function of the image processingdevice 20 may be shared and realized by a plurality of computers.

The numbers of DTP devices 12, database servers 14, management computers16, image processing devices 20, printing control devices 22, printingdevices 24, image reading devices 26 and plate making devices which areincluded in the present system are not particularly limited.

A network system in which the DTP device 12, the database server 14, themanagement computer 16, the image processing device 20 and the printingcontrol device 22 are connected to the electric communication line 28has been described in the present example. However, when the presentinvention is implemented, the respective elements may not be necessarilyconnected to the communication network.

<Hardware Configuration of Image Processing Device 20>

FIG. 2 is a block diagram showing a hardware configuration example ofthe image processing device 20. The image processing device 20 of thepresent example is realized using a personal computer (PC). That is, theimage processing device 20 includes a PC main body 30, a display device32, and an input device 34. The term “PC” means a personal computer, andincludes various types of computers such as a desktop computer, a laptopcomputer and a tablet computer. The PC main body 30 includes a centralprocessing unit (CPU) 41, a memory 42, a hard disk drive (HDD) 43 as astorage device that stores and retains various programs or data items,an input interface unit 44, a communication interface unit 45 fornetwork connection, a display control unit 46, and a peripheral deviceinterface unit 47.

The image reading device 26 described in FIG. 1 may be connected to theimage processing device 20 through the peripheral device interface unit47 of FIG. 2.

For example, as the display device 32, a liquid crystal display or anorganic electro-luminescence (EL) display may be used. The displaydevice 32 is connected to the display control unit 46. The input device34 may adopt various means such as a keyboard, a mouse, a touch paneland a trackball, and may be an appropriate combination thereof. In thepresent example, as the input device 34, a keyboard and a mouse areused. The input device 34 is connected to the input interface unit 44.The display device 32 and the input device 34 function as a userinterface (UI). An operator (user) may input various information itemsby using the input device 34 while viewing the content displayed on ascreen of the display device 32, and may operate the image processingdevice 20 or the printing device 24. The operator can comprehend (check)a system state through the display device 32.

Various programs or data items required for the image processing arestored in the hard disk drive 43. For example, chart data of acharacteristic parameter acquisition chart, a calculation program forgenerating a characteristic parameter, an image processing programincluding a process of generating the halftone processing rule, and aprogram of generating a halftone selection chart are stored. Theprograms stored in the hard disk drive 43 are loaded to the memory 42,and the loaded programs are executed by the CPU 41. Thus, various meansdefined by the programs are functioned.

The same hardware configurations as those of the PC main body 30, thedisplay device 32 and the input device 34 shown in FIG. 2 may be adoptedas the hardware configurations of the DTP device 12, the database server14, the management computer 16 and the printing control device 22described in FIG. 1.

<Description related to Function of Image Processing Device 20>

FIG. 3 is a block diagram for describing a function of an imageprocessing device 20 according to a first embodiment. The imageprocessing device 20 includes a control unit 50, a characteristicparameter acquisition unit 52, a characteristic parameter storage unit54, a priority parameter retention unit 56, a halftone processgeneration unit 58, and a halftone-processing-rule storage unit 60.

The control unit 50 controls the operations of the respective units ofthe image processing device 20. The characteristic parameter acquisitionunit 52 is means for acquiring a characteristic parameter related to thecharacteristics of the printing system 10 including the printing device24 described in FIG. 1. For example, in an ink jet printing system, asthe characteristic parameter related to the characteristics of theprinting system, there are resolution, the number of nozzles, an inkkind, an average dot density, an average dot diameter, an average dotshape, and a dot density, a dot diameter, a dot shape, a dot formingposition shift, non-jetting and landing interference of each printingelement. Information related to at least one of the parameters describedherein, preferably, the plurality of parameters is acquired through thecharacteristic parameter acquisition unit 52.

The dot forming position shift is a concept for comprehensivelyrepresenting that a position in which a dot is actually formed isshifted from an ideal dot forming position in which a dot is formed. The“ideal position in which a dot is formed” is a target position in designand indicates a dot forming position in a state in which it is assumedthat there is no error. There are various causes of the dot formingposition shift. For example, there are the bending of each printingelement in a jetting direction, a variation in jetting speed of eachprinting element, a shift in jetting timing of each printing element, ashift in jetting timing between outward scanning and inward scanning inbidirectional scanning, a shift in position between the outward scanningand the inward scanning in the bidirectional scanning, the bending ofthe outward scanning and the inward scanning in the bidirectionalscanning in the jetting direction, a shift in jetting timing of eachscanning path of a plurality of scanning paths, a shift in position ofeach scanning path, and bending of each scanning path in the jettingdirection. The dot forming position shift is generated by the causeincluding at least one of the causes described herein. The “bending of anozzle in a jetting direction” means “jetting bending”.

Among various characteristic parameters described above, sinceparameters such as a dot density, a dot diameter, a dot shape andlanding interference of each printing element are changed depending on acombination of the characteristics of the recording head, an ink or aprinting medium to be used and the dot forming position shift or thenon-jetting is changed by the state of the recording head, ifappropriate values are input as these various parameters by the user, anoperation load is increased. The characteristics of the recording headinclude a waveform or a frequency of a driving signal applied to therecording head when the ink is jetted, and the state of the recordinghead includes, for example, the inclining or bending of the recordinghead and indicates a distance from the printing medium or a state ofeach printing element.

The printing element means a recording element serving to record the dotin the printing device 24. In the case of an ink jet printing device, anozzle for jetting an ink in an ink jet head corresponds to the“printing element”. In the case of a printing device using a reliefplate, a relief of a protrusion portion of a halftone dot in the platecorresponds to the “printing element”.

The characteristics of the printing system include at least one ofindividual recording characteristics of a plurality of printing elementsor common characteristics of the plurality of printing elements. Theindividual recording characteristics of the printing elements include atleast one of a dot density, a dot diameter, a dot shape, a dot recordingposition error, or unrecordable abnormality. In the ink jet printingdevice, the dot recording position error corresponds to the “dot formingposition shift”, and the unrecordable abnormality corresponds to the“non-jetting”.

The “common characteristics” of the plurality of printing elementsinclude at least one of an average dot density, an average dot diameter,an average dot shape, or landing interference.

A method of acquiring the characteristic parameter may be performed bycausing the printing device 24 to output the characteristic parameteracquisition, causing the image reading device 26 (see FIG. 1) such asthe inline scanner or the office scanner to read the characteristicparameter acquisition chart and to analyze the read image.

Among the resolution, the number of nozzles, the ink kind, the averagedot density, the average dot diameter, the average dot shape, and thedot density, the dot diameter, the dot shape, the dot forming positionshift, the non-jetting and the landing interference of each printingelement, the resolution, the number of nozzles and the kind of the inkare characteristic parameters related to the system specification.

Accordingly, it is preferable that the characteristic parameters relatedto the system specifications are previously retained within the system.It is preferable that data of the characteristic parameter acquisitionchart for acquiring the parameters related to the individualcharacteristics of the system is generated based on the resolution, thenumber of nozzles and the kind of the ink which are the characteristicparameters related to the system specification or data of thecharacteristic parameter acquisition chart is selected from data itemsof a plurality of characteristic parameter acquisition charts that ispreviously retained within the system, the characteristic parameteracquisition chart is output by the printing device 24 of the printingsystem 10, the characteristic parameter acquisition chart is read fromthe image reading device 26 (see FIG. 1), and various characteristicparameter related to the characteristics specific to the printing device24 are acquired.

In addition, as the characteristic parameters related to the systemspecification, there are a droplet kind, unidirectional scanning orbidirectional scanning, a scanning speed, the amount of transportedprinting media, and a jetting frequency. It is preferable that the dataof the characteristic parameter acquisition chart is generated based onat least one the characteristic parameter related to the systemspecification which includes the characteristic parameters.

The image processing device 20 of the present example includes acharacteristic-parameter-acquisition-chart generation unit 62 and animage analysis unit 64, as means for automatically acquiring thecharacteristic parameters related to the characteristics of the printingsystem 10.

The characteristic-parameter-acquisition-chart generation unit 62 is aprocessing unit that generates chart data for the characteristicparameter acquisition chart including the parameters for acquiring thecharacteristic parameters related to the characteristics of the printingsystem. The chart data generated by thecharacteristic-parameter-acquisition-chart generation unit 62 is sent tothe printing control device 22 (see FIG. 1) through the data output unit66, and the characteristic parameter acquisition chart is printed by theprinting device 24.

The combination of the characteristic-parameter-acquisition-chartgeneration unit 62 and the configuration in which the characteristicparameter acquisition chart is output by the printing device 24 (seeFIG. 1) based on the chart data generated by thecharacteristic-parameter-acquisition-chart generation unit 62corresponds to one example of“characteristic-parameter-acquisition-chart output means”. Thecharacteristic-parameter-acquisition-chart generation unit 62corresponds to one example of“characteristic-parameter-acquisition-chart generation means”.

An example of the characteristic parameter acquisition chart will bedescribed below in detail, but a single dot pattern of each printingelement by a head of each color of the ink may be the characteristicparameter acquisition chart. The single dot pattern is a pattern whichis obtained by isolating each dot from another dot without overlappinganother dot and individually jetting dots. The chart of the single dotpattern is read, and thus, the parameters related to the dot density,dot diameter, dot shape, dot forming position shift and non-jetting ofeach printing element can be read.

The characteristic parameter acquisition chart may include a continuousdot pattern in which a plurality of dots overlaps in addition to thesingle dot pattern. The continuous dot pattern may include a continuousdot pattern in which an inter-dot distance between two dots is changedand the dots are jetted such that a part of each dot overlaps a part ofanother dot. Such a continuous dot pattern is used to acquire aparameter of a dot deformation amount due to landing interference.

In a case where there the droplet kind of the present printing system 10is one, a single dot pattern may be formed by independently jetting onekind of dot, and a continuous dot pattern may be formed by jetting aplurality of dots so as to overlap each other. In a case where thedroplet kind of the present printing system is plural, a single dotpattern may be formed by independently jetting the respective kinds ofdots, and a continuous dot pattern may be formed by jetting acombination of the respective kinds of dots so as to overlap each other.

When the characteristic parameter acquisition chart is output, a singledot of the same printing element may be printed multiple times, and theaverage values of the dot densities, the dot diameters, the dot shapesand the dot forming position shifts thereof may be the dot density, thedot diameter, the dot shape and the dot forming position shift of theprinting element. An average dot density, an average dot diameter and anaverage dot shape may be acquired by averaging the dot densities, thedot diameters and the dot shapes of the respective printing elements.

In a case where a tolerance deign to the system error is performed, avariance σ² indicating a variation in an average value of measurementvalues acquired by reading the characteristic parameter acquisitionchart may be calculated, and a value of a standard deviation σ which isthe square root of the variation σ² may be used as a predeterminedamount of an error to be used later.

A printing result of the characteristic parameter acquisition chartprinted by the printing device 24 is read by the image reading device26, and the data of the read image of the characteristic parameteracquisition chart is acquired.

The image analysis unit 64 functions as a characteristic parametergeneration unit that analyzes the read image read by the image readingdevice 26 and generates information of the characteristic parameter. Theinformation of the characteristic parameter is automatically acquiredfrom the characteristic parameter acquisition chart by the imageanalysis unit 64. The image analysis unit 64 corresponds to one exampleof “image analysis means”.

That is, the characteristic parameter acquisition unit 52 of the imageprocessing device 20 is configured to automatically acquire thecharacteristic parameter from a result measured by analyzing the readimage of the characteristic parameter acquisition chart. The combinationof the image analysis unit 64 and the characteristic parameteracquisition unit 52 correspond to one example of “characteristicparameter acquisition means”.

The information of the characteristic parameter acquired through thecharacteristic parameter acquisition unit 52 is stored in thecharacteristic parameter storage unit 54. The characteristic parametersrelated to the system specification may be previously stored in thecharacteristic parameter storage unit 54.

The halftone process generation unit 58 generates the halftoneprocessing rule that defines the processing content of each of two ormore kinds of halftone processes of which the balances of priority for aplurality of requirements required in the halftone process are differentbased on the characteristic parameters. The image processing device 20includes an image quality evaluation processing unit 74 that includes asimulation image generation unit 68 and an evaluation value calculationunit 70, and the halftone process generation unit 58 generates the twoor more kinds of halftone processing rules in cooperation with the imagequality evaluation processing unit 74. The halftone process generationunit 58 corresponds to one example of “halftone process generationmeans”. The evaluation value calculation unit 70 corresponds to oneexample of “evaluation value calculation means”. The image qualityevaluation processing unit 74 corresponds to one example of “imagequality evaluation means”.

The image quality evaluation processing unit 74 performs an optimumsearching process in which an evaluation value is enhanced whilerepeatedly performing the generation of the simulation image and thecalculation of the evaluation value of the image quality for thesimulation image. The halftone parameter is determined through theprocess performed by the image quality evaluation processing unit 74.

The multiple kinds of halftone processing rules generated by thehalftone process generation unit 58 are registered in thehalftone-processing-rule storage unit 60. For the sake of convenience inthe illustration, it has been described in FIG. 3 that two kinds ofdifferent halftone processing rules 1 and 2 are generated and thehalftone processing rules 1 and 2 are stored and retained in thehalftone-processing-rule storage unit 60. However, in a case where K isan integer which is equal to or greater than 2, K or more kinds, thatis, multiple kinds of halftone processing rules may be generated. All ora part of the K kinds of generated halftone processing rules 1, 2, . . ., and K may be registered as a line-up in the halftone-processing-rulestorage unit 60. The halftone-processing-rule storage unit 60corresponds to one example of halftone registration means. Multiplekinds of halftone processing rules as candidates of the halftone processcapable of being used in the printing system 10 may be registered in thehalftone-processing-rule storage unit 60. The halftone processing ruleactually used in the printing is determined among the plurality ofhalftone processing rules generated in the halftone process generationunit 58.

The image processing device 20 of the present example includes ahalftone-selection-chart generation unit 76 as selection supportingmeans for selecting any one halftone processing rule of the plurality ofhalftone processing rules.

The halftone-selection-chart generation unit 76 generates chart data ofthe halftone selection chart in which the printing results of thehalftone images acquired by two or more kinds of halftone processingrules are arranged so as to be compared. The chart data generated by thehalftone-selection-chart generation unit 76 is sent to the printingcontrol device 22 (see FIG. 1) through the data output unit 66, and thehalftone selection chart is printed by the printing device 24.

The combination of the halftone-selection-chart generation unit 76 andthe printing device 24 corresponds to one example of“halftone-selection-chart output means”.

A user can select a desired halftone processing rule while viewing theoutput result of the halftone selection chart. A selection operation ofthe halftone processing rule performed by the user is performed usingthe input device 34. The input device 34 functions as “halftoneselection operating means” for allowing the user to perform theselection operation of the desired halftone processing rule. That is,the input device 34 functions as halftone selection operating means forreceiving a user operation for allowing the user to select the kind ofany one halftone process from the two or more kinds of halftoneprocesses used to generate the halftone selection chart.

The input device is not limited to the function of selecting thehalftone processing rule by the user, and may have a function ofallowing the system to automatically select one halftone processingrule. In this case, it is necessary to previously retain priorityparameters related to the priorities for the plurality of requirementsin the halftone process. Priority parameters that designate the balancesof priority related to the plurality of requirements are stored in thepriority parameter retention unit 56. The priority parameter retentionunit 56 corresponds to one example of priority parameter retentionmeans.

The priority parameter may be freely input by the user through the inputdevice 34. The balances of priority may be set and the setting contentmay be changed. Alternatively, as the priority parameter, one kind ormultiple kinds of selection candidates may be previously prepared on thesystem. In a case where multiple kinds of selection candidates relatedto the setting of the priority parameter are prepared, the user canselect any one selection candidate through the input device 34 inconsideration of the printing purpose or usage and productivity.

The balances of priority for the requirements may be designated by thepriority parameter, and thus, one optimum halftone processing rulerecommended on the system may be uniquely determined according to thepriority parameter specified by the priority parameter retention unit56. The automatic selection function may be realized by the control unit50, and the configuration of the control unit 50 serving to perform theautomatic selection process corresponds to one example of halftoneautomatic selection means.

The input device 34 functions as a priority input unit for allowing theuser to input a setting related to the priority for each requirement.The halftone processing rule (that is, a combination of the halftonealgorithm and the halftone parameter) based on the setting of thepriority and the halftone processing rule which is the balance of thepriority symmetrical with the balances of priority related to the usersetting may be generated depending on the priority set by the user, andthese halftone processing rules may be compared.

The balance of the priority may be slightly adjusted with the priorityset by the user as its reference, and the plurality of halftoneprocessing rules may be generated based on the plurality of set balancesof the priority.

The image processing device 20 has a function of performing the halftoneprocess on the data of the continuous-tone image according to thegenerated halftone processing rule. That is, the image processing device20 includes an image input unit 77, a color conversion processing unit78, and a halftone processing unit 80.

The image input unit 77 is an input interface unit that inputs the dataof the manuscript image, and functions as an image data acquisitionunit. The image input unit 77 may be a data input terminal that inputsthe manuscript image data from another signal processing unit outside orinside the device. As the image input unit 77, a wired or wirelesscommunication interface unit may be adopted, a media interface unit thatperforming reading and writing on an external storage medium (removabledisk) such as a memory card may be adopted, or an appropriatecombination thereof may be adopted.

The color conversion processing unit 78 performs the color convertingprocess on the manuscript image data by using color profile inaccordance with the form of ICC profile by the International ColorConsortium (ICC), and generates a color image signal appropriate foroutputting performed by the printing device 24. In a case where fourcolor inks of CMYK are used in the printing device 24, image signals ofCMYK are generated by the color conversion processing unit 78. Inaddition to CMYK, in a case where six color inks which include lightmagenta (LM) and light cyan (LC) are used, image signals which includethe respective color components of CMYK, LM and LC are generated by thecolor conversion processing unit 78.

The halftone processing unit 80 performs the halftone process on thecontinuous-tone images of the respective colors by using the halftoneprocessing rule generated by the halftone process generation unit 58,and generates the halftone image. The data of the halftone imagegenerated by the halftone processing unit 80 is sent to the printingcontrol device 22 (see FIG. 1) through the data output unit 66, and theprinting is performed by the printing device 24.

A method of acquiring the printed material by performing the printing onthe printing medium by the printing device 24 based on the halftoneimage generated through the process by the halftone processing unit 80may be comprehended as a method of manufacturing the printed material.

The image quality evaluation processing unit 74 of the image processingdevice 20 may calculate the evaluation value of the printing halftoneimage in cooperation with the halftone processing unit 80. Informationof the evaluation value related to the halftone image generated by thehalftone processing unit 80 may be displayed on the screen of thedisplay device 32, and may be supplied to the outside through the dataoutput unit 66.

<Procedure of Determining Halftone Processing Rule in Printing System>

A method of determining the halftone processing rule in the printingsystem 10 according to the present embodiment will be described indetail. FIG. 4 is a flowchart showing an example of a method ofgenerating the halftone processing rule according to the presentembodiment.

Initially, in order to acquire the characteristic parameters related tothe characteristics of the printing system 10, the characteristicparameter acquisition chart is generated, and the characteristicparameter acquisition chart is output by the printing device 24 (seeFIG. 1) (step S10 of FIG. 4). Step S10 corresponds to one example of a“characteristic-parameter-acquisition-chart output step”.

Subsequently, the characteristic parameter acquisition chart output instep S10 is read (step S11). In step S11, the printed material of thecharacteristic parameter acquisition chart is read by the image readingdevice 26 (see FIG. 1), and the read image of the characteristicparameter acquisition chart is acquired. Step S11 of FIG. 4 correspondsto one example of an “image reading step”.

Subsequently, the read image acquired in step S11 is analyzed, and thecharacteristic parameters related to the characteristics of the printingsystem are acquired (step S12). Step S12 is one example of a“characteristic parameter acquisition step”.

Subsequently, the two or more kinds of halftone processing rules ofwhich the priorities for the requirements of the halftone process aredifferent are generated (step S14). When the halftone processing rule isgenerated, multiple kinds of halftone processing rules are generatedbased on the priority parameter and the characteristic parameter. StepS14 is one example of a halftone process generation step.

The halftone selection chart is output using the respective generatedhalftone processing rules (step S16). Steps S16 is one example of a“halftone-selection-chart output step”.

The user can select any one halftone processing rule while viewing theoutput result of the halftone selection chart. The halftone processingrule used in the printing is determined based on the selection operationof the user (step S18). That is, in step S18, the user operation forallowing the user to select the kind of any one halftone process fromthe two or more kinds of halftone processes used to generate thehalftone selection chart is received, and the halftone processing ruleis determined based on the selection operation by the user. Step S18 isone example of a halftone selection operating step.

<Example of Characteristic Parameter Acquisition Chart>

A specific example of the characteristic parameter acquisition chartused in the characteristic parameter acquisition step described in stepS12 of FIG. 4 will be described.

FIG. 5 is a diagram showing an example of a characteristic parameteracquisition chart 100. Here, an example in which single dot patterns102C, 102M, 102Y and 102K, first continuous dot patterns 104C, 104M,104Y and 104K and second continuous dot patterns 106C, 106M, 106Y and106K on a printing medium 101 are jetted by the nozzles which are theprinting elements in the recording heads of the respective colors ofcyan, magenta, yellow and black is illustrated. The single dot patterns102C, 102M, 102Y and 102K are discrete dot patterns in which dots arediscretely recorded in an isolation state in which the single dot isisolated from another dot. The first continuous dot patterns 104C, 104M,104Y and 104K and the second continuous dot patterns 106C, 106M, 106Yand 106K are continuous dot patterns in which two or more dots arerecorded so as to be in contact.

The single dot patterns 102C, 102M, 102Y and 102K, the first continuousdot patterns 104C, 104M, 104Y and 104K and the second continuous dotpatterns 106C, 106M, 106Y and 106K correspond to one example of a“pattern for acquiring the characteristic parameters”. The single dotpatterns 102C, 102M, 102Y and 102K correspond to one example of a“discrete dot pattern”. The first continuous dot patterns 104C, 104M,104Y and 104K and the second continuous dot patterns 106C, 106M, 106Yand 106K correspond to one example of a “continuous dot pattern”.

FIG. 6 is a schematic plan view of a serial scan type ink jet printingdevice used to draw the characteristic parameter acquisition chart ofFIG. 5. In FIG. 6, for the sake of convenience in the illustration, onlyfour nozzles of the respective colors are illustrated by reducing thenumber of nozzles of the recording heads of the respective colors. Thenumber of nozzles, the arrangement form of nozzles, and the nozzledensity may be variously designed.

As shown in FIG. 6, a head unit 110 of the serial scan type ink jetprinting device is configured such that a cyan recording head 112C thatjets an cyan ink, a magenta recording head 112M that jets a magenta ink,an yellow recording head 112Y that jets a yellow ink and a blackrecording head 112K that jets a black ink are mounted on a carriage 114and can be moved in reciprocating motion in an X direction of FIG. 6. AY direction perpendicular to the X direction is a transport direction ofthe printing medium 101. The X direction corresponds to a “main scanningdirection”, and the Y direction corresponds to a “sub scanningdirection”.

The detailed structure of the respective recording heads of the cyanrecording head 112C, the magenta recording head 112M, the yellowrecording head 112Y and the black recording head 112K are not shown.However, each of the ink jet type recording heads includes jettingenergy generating elements (for example, piezoelectric elements or heatgenerating elements) that generate jetting energy required to jet theinks depending on the respective nozzles. The respective recording heads(112C, 112M, 112Y and 112K) jet ink liquid droplets on demand inresponse to driving signals and jetting control signals applied from theprinting control device 22 (see FIG. 1).

The droplets are jetted from the respective nozzles 118C of the cyanrecording head 112C in an appropriate timing while moving the carriage114 of FIG. 6 in the X direction, and thus, the single dot patterndenoted by reference numeral 102C of FIG. 5 can be formed. After thesingle dot pattern 102C is drawn using the cyan ink, a recording regionin the printing medium 101 is changed by transporting the printingmedium 101 in the Y direction, and the droplets are jetted from therespective nozzles 118C of the cyan recording head 112C in anappropriate timing while moving the carriage 114 in the X direction.Thus, the first continuous dot pattern denoted by reference numeral 104Cof FIG. 5 can be formed. After the first continuous dot pattern 104C isdrawn using the cyan ink, the recording region in the printing medium101 is changed by transporting the printing medium 101 in the Ydirection, and the droplets are jetted from the respective nozzles 118Cof the cyan recording head 112C in an appropriate timing while movingthe carriage 114 in the X direction. Thus, the second continuous dotpattern denoted by reference numeral 106C of FIG. 5 can be formed.

In the first continuous dot pattern 104C and the second continuous dotpattern 106C, the inter-dot distances between the dots overlapping eachother are differently set. Multiple kinds of continuous dot patterns arerecorded by changing the inter-dot distances, and thus, thecharacteristic parameter related to the relationship between aninter-dot distance d and the deformation amount due to the influence ofthe landing interference can be comprehended.

Although it has been described in FIG. 5 that two kinds of continuousdot patterns (104C and 106C) in which the inter-dot distances aredifferent are used, three or more kinds of continuous dot patterns maybe formed by changing the inter-dot distances.

Subsequently to the recording of the dot patterns (102C, 104C and 106C)using the cyan ink, the droplets from the respective nozzles 118M of themagenta recording head 112M, the droplets from the respective nozzles118Y of the yellow recording head 112Y, and the droplets from therespective nozzles 118K of the black recording head 112K aresequentially jetted in a similar manner. Thus, the characteristicparameter acquisition chart 100 shown in FIG. 5 is generated.

Information items related to the dot density, the dot diameter, the dotshape, the dot forming position shift and the non-jetting of eachprinting element of each color may be acquired from each of the singledot patterns 102C, 102M, 102Y and 102K of the respective colors. Astatistical process is performed on the measurement results of aplurality of single dots, and thus, it is possible to acquire theaverage dot density, the average dot diameter, the average dot shape andthe standard deviation σ (square root of the variation σ²) thereof. Thestandard deviation σ or the variance σ² calculated for at least one itemof the dot density, the dot diameter, the dot shape or the dot formingposition shift of each printing element corresponds to one example of“dispersion information related to dispersion of a dot”.

Information of the characteristic parameter related to the landinginterference can be acquired from the first continuous dot patterns104C, 104M, 104Y and 104K and the second continuous dot patterns 106C,106M, 106Y and 106K of the respective colors. The characteristicparameter related to the landing interference refers to informationrelated to a change in inter-dot distance, a change in dot density or achange in dot shape due to the influence of the landing interferencewhich is the interaction between the dots overlapping each other.

<Characteristic Parameter related to Landing Interference>

FIGS. 7 and 8 are explanatory diagrams of the characteristic parameterrelated to the landing interference. The left fields of FIG. 7 representthat the set value of the inter-dot distance between two dots when twodots are continuously jetted by partially overlapping the two dots isdifferently set in three steps of d1, d2 and d3, and the right fields ofFIG. 7 represent that the inter-dot distance is changed due to theinfluence of the landing interference in a case where the droplets arejetted in the set values of the inter-dot distances d1, d2 and d3. Theinter-dot distance means a distance between the centers of the dots.

As shown in the drawings, it is assumed that actual inter-dot distancesare u1, u2 and u3 (u1>u2>u3) for the inter-dot distances d1, d2 and d3(d1>d2>d3) as the set values. Since the dots are drawn due to thelanding interference, the relationships of d1>u1, d2>u2, and d3>u3 aresatisfied.

The data of the change in the inter-dot distance due to the influence ofthe landing interference is acquired by changing the setting of theinter-dot distance, and thus, it is possible to acquire landinginterference data shown in FIG. 8. A horizontal axis of FIG. 8 denotes aset value of the inter-dot distance, and “R” represents a radius of thedot. A vertical axis of FIG. 8 denotes the change amount by which theinter-dot distance is changed due to the influence of the landinginterference, and represents an absolute value of |di−ui| of FIG. 7(i=1, 2 and 3). “2R” on the horizontal axis of FIG. 8 represents aposition in which two dots are circumscribed. If the inter-dot distanceis greater than 2R, since the dots do not overlap each other, there isno influence of the landing interference. In a case where the inter-dotdistance is set to be smaller than 2R, the dots overlap each other, andthe dots are drawn due to the landing interference. Thus, the inter-dotdistance is changed.

Although it has been described in FIG. 8 that the influence of thelanding interference is the “change amount of the inter-dot distance”,the influence of the landing interference may be measured as a change indot density or a change in dot shape.

The landing interference data parameterized as a function of theinter-dot distance d can be acquired from the reading result of thefirst continuous dot patterns 104C, 104M, 104Y and 104K and the secondcontinuous dot patterns 106C, 106M, 106Y and 106K in the characteristicparameter acquisition chart 100 described in FIG. 5.

The parameters related to the landing interference are calculated forthe respective printing elements (in this example, the respectivenozzles), and are averaged. The value acquired by averaging theparameters for each color may be retained, or the value acquired byaveraging the parameters for all the colors may be retained as a commonparameter.

It has been described in FIG. 5 that the single dot pattern and thecontinuous dot pattern are used in a case where it is assumed that thedroplet kind is one for each color of CMYK. However, in a case where thedroplet kind is plural, it is assumed that the single dot pattern isformed by independently jetting the respective kinds of dots and thecontinuous dot pattern is formed by jetting the combination of therespective kinds of dots so as to overlap each other. The parametersrelated to the landing interference for the combination of therespective droplet kinds are acquired. The continuous dot pattern may beformed by jetting the combination of the dots of the respective CMYKcolors so as to overlap each other, and the parameters related to thelanding interference may be acquired for the combination of the dots ofthe respective colors.

As the chart for acquiring the parameters related to the landinginterference, the chart in which the inter-dot distance between theplurality of dots is changed and a recording time difference between theplurality of dots is changed may be output. For example, in thecondition in which a time difference when the plurality of dots isrecorded is one path, two paths, 3 paths, . . . , the chart in which thetime difference is set in a plurality of levels and the dots are incontact in the time difference in the plurality of levels may be output.The recording time difference corresponds to a jetting time difference.

For example, in the condition in which two dots jetted so as to overlapeach other in the first continuous dot pattern and the second continuousdot pattern of the respective CMYK colors of FIG. 5 are respectively Dot1 and Dot 2, the continuous dot pattern in which Dot 1 and Dot 2 arecontinuously jetted by moving the carriage 114 in the X direction onceis formed and the continuous dot pattern in which after Dot 1 is jettedby moving the carriage 114 in the X direction once and Dot 2 is jettedby moving the carriage 114 in the X direction twice without transportingthe printing medium 101 in the Y direction is formed, and the continuousdot pattern in which after Dot 1 is jetted by moving the carriage 114 inthe X direction once, Dot 2 is jetted by moving the carriage 114 in theX direction three times without transporting the printing medium 101 inthe Y direction is formed, the continuous dot pattern in which Dot 1 andDot 2 are in contact in the time difference (path difference) atmultiple levels may be formed.

<Requirements for Halftone Process>

For example, as the requirements required in the halftone process, thereare the following requirements. That is, as a first classification (a)of the requirement, there are image quality, system cost, halftonegenerating time, and halftone processing time. As a secondclassification (b) of the requirement, there are “granularity” and“tolerance to a system error” which are related to the image quality.The plurality of requirements has the trade-off relationship. As thetolerance to the system error, there is “tolerance to environmentchange”. For example, since the density of the ink and the spread amountof the dot are changed due to the influence of temperature or humidity,it is considered that the halftone processing rule is designed bysimulating the influence thereof as the tolerance to the environmentchange.

In the present embodiment, the two or more kinds of halftone processingrules of the halftone process of which the balances of priority for theplurality of requirements required in the halftone processing aredifferent are generated. However, the “plurality of requirements”includes at least two items of the image quality, the system cost, thehalftone generating time, the halftone processing time, the tolerance tothe system error or the tolerance to the environment change, which aredescribed above.

<Advantages and Disadvantages of Halftone Algorithm and EachRequirement>

The advantages and disadvantages of various halftone algorithms for therespective requirements such as the image quality, the system cost, thehalftone generating time and the halftone processing time of the firstclassification (a) are represented in the table of FIG. 9. Here, as thehalftone algorithm, three kinds of methods including the dither method,the error diffusion method, and the direct binary search (DBS) methodare compared.

The system cost includes cost related to another system specificationsuch as central processing unit (CPU) performance or memory capacityrequired to realize the function of the halftone process. The halftonegenerating time is time necessary to generate the halftone processingrule, and includes, for example, time necessary for calculation fordetermining the halftone parameter. The halftone processing time is timenecessary for process of converting the data of the continuous-toneimage into the data of the halftone image by using the generatedhalftone processing rule.

If three kinds of halftone algorithms including the dither method, theerror diffusion method and the DBS method are compared, as for the imagequality, the image quality is relatively low in the dither method, theimage quality is relatively high quality in the DBS method, and theimage quality is medium image quality therebetween in the errordiffusion method. As for the system cost, the cost is relatively low inthe dither method, and the cost is relatively high in the DBS method.The system cost in the error diffusion method is a medium level betweenthe dither method and the DBS method. The halftone generating time andthe halftone processing time are relatively short in the dither method,and are relatively longer time in the DBS method. The halftonegenerating time and the halftone processing time are medium levelsbetween the dither method and the DBS method.

The advantages and disadvantages for the respective requirements arechanged by the setting of the halftone parameter even in the samehalftone algorithm in addition to the relative advantages anddisadvantages due to the kind of the halftone algorithm shown in FIG. 9.For example, in a case where the halftone algorithm is the dithermethod, the image quality becomes higher as the dither size becomeslarger, but the system cost becomes higher and the halftone generatingtime or the halftone processing time becomes longer.

In a case where the halftone algorithm is the error diffusion method,the image quality becomes higher as an error diffusion matrix sizebecomes larger or as the number of gradation sections to which an errordiffusion matrix is applied becomes greater, but the system cost becomeshigher for another requirement, and the halftone generating time and thehalftone processing time becomes longer.

In a case where the halftone algorithm is the DBS method, the imagequality becomes higher as the number of times pixels are updated becomesgreater or as an exchange pixel range becomes wider, but the system costbecomes higher for another requirement, and the halftone generating timeor the halftone processing time becomes longer.

As for the second classification (b) of the requirement, the erroroccurs in the characteristic parameters such as the dot density, the dotdiameter, the dot shape, the dot forming position shift and thenon-jetting due to the printing order, the drawing path or the jettingtiming, and the tolerance design to the system error can be performedsuch that a deterioration in granularity or stripe occurrence issuppressed, but the granularity in a state in which there is no error bythe tolerance design is deteriorated. That is, the tolerance to thesystem error and the granularity have the trade-off relationship.

For example, the printing order as the cause of the system error is theorder in which the ink colors overlap each other. The printing order mayinclude the order of an outward path and an inward path in serial scantype head scanning. The path is the order of the paths in a drawing modein which the drawing is completed multipath by the serial scan type inkjet head. In the case of a single path printer, a line in the mainscanning direction corresponds to the “path”. For example, in a casewhere the jetting is performed while sending the printing medium, thetiming is taken on the assumption that the error occurs in the landingposition or the dot shape by the jetting timing due to the influence ofthe transport error of the printing medium.

Since the characteristic parameters such as the dot density, the dotdiameter, the dot forming position shift or the non-jetting are changedby the temporal state change of the printing element, these errors areregarded as the system error. It is difficult to reproduce thesimulation by accurately acquiring the change of the dot density, theshape or the position due to the landing interference as the parameterfrom only the characteristic parameter acquisition chart shown in FIG.5, and such a difference from the reality is regarded as the systemerror.

That is, the tolerance deign is performed by regarding the restrictionsof the temporal state change of the system, the characteristic parameteracquisition chart or the image reading device 26 and the differencebetween the simulation image and the reality occurring by the limitationof the simulation model as the system error, optimizing the granularityin a state in which there is no difference and suppressing thedeterioration in granularity of a real image or the occurrence of thestreak even though there are such differences.

In the dither method, for example, in the printing system such as asingle path printer in which the respective printing elements areindependently present in a range in which the width direction of theprinting medium is wide, it is difficult to perform the halftone designsuch that the granularity is optimized by reflecting the characteristicssuch as the dot density, the dot diameter, the dot shape, the dotforming position shift or the non-jetting of each printing element.

Accordingly, in this case, the design is also performed such that thegranularity is optimized based on the information of the average dotdensity, the dot diameter or the dot shape for each ink droplet and thetolerance to the error such as the dot density, the dot diameter, thedot shape, the dot forming position shift or the non-jetting due to theindividual characteristic of the plurality of printing elements isgiven.

<Description Using Specification Example>

In the image processing device 20 of the present example, two or morehalftone processing rules are set depending on the priorities of therespective requirements based on the advantages and disadvantages of therespective requirements. The halftone processing rule is specified bythe combination of the halftone algorithm and the halftone parameter.

Setting Example 1

For example, as a setting example of the priority, in a case where thesetting is performed such that the image quality is important for thefirst classification (a) and the granularity is important for the secondclassification (b), the following halftone processing rule may bedetermined as the halftone processing rule corresponding to the setting(Setting Example 1) of the priority.

Halftone algorithm: DBS method

-   -   Halftone parameter: number of times pixel is updated=large, and        exchange pixel range=large    -   Tolerance design to system error: no

An appropriate value belonging to a relatively large value of aplurality of value candidates capable of being selected on the system isset to a specific value that specifies the number of times the pixelrelated to the halftone parameter is updated or a specific value thatspecifies the exchange pixel range.

In the DBS method, the halftone processing rule is determined by simplydesignating the number of times the pixel is updated and the exchangepixel range as the halftone parameter.

Setting Example 2

For example, as another setting example of the priority, in a case wherethe setting is performed such that the halftone processing time isimportant for the first classification (a) and the tolerance to thesystem error is important for the second classification (b), thefollowing halftone processing rule can be determined as the halftoneprocessing rule corresponding to the setting (Setting Example 2) of thepriority.

Halftone algorithm: dither method

-   -   Halftone parameter: dither mask size=small    -   Tolerance design to system error: error of ±10 micrometers [μm]        is added, and tolerance to “streaks” is considered

Setting is performed such that granularity evaluation parameter α=1 andstreak evaluation parameter β=1.

An appropriate value belonging to a relatively small value of aplurality of value candidates capable of being selected on the system isset to a specific value that specifies a dither mask size related to thehalftone parameter. In the illustrated Setting Example 2, as for thesecond classification (b), since the extent of the system error is notunderstood in some cases and how much the system error influences thestreak quality or granularity of a real image is not still understood, aplurality of values may be set depending on the priority of thetolerance to the system error. For example, a plurality of values suchas “±10 micrometers [μm]”, “±20 micrometers [μm]”, . . . may be set tothe error amount. As for the simulation of the landing interference, aplurality of settings such as “non-execution setting”, “executionsetting”, “setting in which only dot movement due to the landinginterference is simulated at the time of execution”, and “setting inwhich a change in dot density or shape as well as the dot movement issimulated” may be performed. As for the setting of the dot movement dueto the landing interference or the change in the density or shape, aplurality of settings may be performed by changing the values using theparameter acquired from the characteristic parameter acquisition chartas its reference.

In a case where the simulation in consideration of the landinginterference is performed, the dot movement and/or dot deformation dueto the landing interference may be given as a function of time as wellas a function of an inter-dot distance.

The setting example is not limited to Setting Examples 1 and 2 describedabove, and the halftone processing rule corresponding to varioussettings of the priority may be generated.

In a case where the dither method or the error diffusion method isselected as the halftone algorithm, a process of generating the halftoneparameter corresponding to each halftone algorithm is performed by aflowchart shown in FIG. 10.

FIG. 10 is a flowchart related to the process of generating the halftoneparameter. The flowchart of FIG. 10 is a common flowchart in both thedither method and the error diffusion method. Here, the dither methodwill be described as an example.

Initially, the halftone parameter is temporarily set (step S22). In thedither method, the matrix size (that is, dither mask size) of the dithermask and each threshold value being determined corresponds to thehalftone parameter being determined. Various sizes such as 32×32, 64×64,128×128 and 256×256 may be used as the dither mask size. The halftoneparameter in a case where the dither mask size is designated representsthe threshold value of the dither mask, and the flowchart of FIG. 10 isrepeated from 0 to the maximum value of the threshold value.

After the halftone parameter is temporarily set in step S22, thehalftone process is subsequently performed using the temporarily sethalftone parameter (step S24). In the dither method, in step S24, dot-ONpixels from a threshold value “0” to a current threshold value areacquired. That is, a halftone image (dot arrangement) on which thehalftone process to which the dither mask is applied has been performedis acquired from a single-gradation input image having a gradation of acurrent threshold value.

Subsequently, a simulation image of a printed image is generated for thehalftone image acquired in step S24 by using the characteristicparameters related to the characteristics of the printing system (stepS26). In step S26, the dots on which the characteristic parametersrelated to the dot density, the dot diameter, the dot shape, the dotforming position shift or the non-jetting of each printing element, oran appropriate combination thereof are reflected are arranged so as tooverlap the pixels of the halftone image, and thus, the simulation imageof the print image is generated from the data of the dot patternindicated by the halftone image.

FIG. 11 is a conceptual diagram of the simulation image. In FIG. 11, therespective lattice cells represent the pixels of the image data. In thedata of the halftone image, the cells of the “dot-ON” pixels arerepresented by a screentone pattern, and the “dot-OFF” pixels arerepresented by a white background.

When the simulation image is generated, the dots on which the recordingcharacteristics such as the dot density, the dot diameter, the dotshape, the dot forming position shift or the non-jetting of eachprinting element serving to record the dot-ON pixels or the appropriatecombination thereof are reflected are arranged on the positions of thedot-ON pixels.

In this case, based on an arrangement state including surrounding dotsor an arrangement state after the dots overlap, the dot shape after thelanding interference may be calculated from the already acquireddeformation parameter of the dot shape due to the landing interference,and the dots may be rearranged. For example, if the dot movementrepresented by a function of f(ya) is caused in the Y direction due tothe influence of the landing interference by an inter-dot distance ya inthe “sub scanning direction” (Y direction of FIG. 11) which is adirection parallel to the transport direction of the printing medium andthe dot movement represented by a function of f(xb) is caused in the Xdirection due to the influence of the landing interference by aninter-dot distance xb in the “main scanning direction” (X direction ofFIG. 11) which is a direction perpendicular to the transport directionof the printing medium, the dot shape caused by the dot movement off(ya)+f(xb) is changed, and thus, the dots are rearranged.

Since the surrounding dots that cause the landing interference arepresent in a diagonal direction as well as the “sub scanning direction”or “main scanning direction” and are influenced by the landingdirection, the dot movement represented by a function of f(c_(n)) iscaused in the direction of the dots due to the influence of the landinginterference by an inter-dot distance c_(n) with surrounding dots n inan arbitrary direction as well as the “sub scanning direction” or “mainscanning direction”, and thus, the dots may be moved byf(ya)+f(xb)+f(c₁)+f(c₂)+ . . . +f(c_(n)), and the dots may berearranged. Of course, since the influence of the landing interferenceis different by the droplet kind, a function f(*) is different by thekind of surrounding dot. “*” represents a parameter. Due to the landinginterference, the dot density or the dot shape as well as the dotmovement may be changed, and the dots may be rearranged.

The inter-dot distance c_(n) and the function f(*) representing the dotmovement may be treated as vector. That is, the parameters ya, xb, andc₁ to c_(n) described with reference FIG. 11 are treated as vectorhaving a direction for the functions of f(ya)+f(xb) andf(ya)+f(xb)+f(c₁)+f(c₂)+ . . . +f(c_(n)). The functions of f(ya)+f(xb)and f(ya)+f(xb)+f(c₁)+f(c₂)+ . . . +f(c_(n)) are treated as vectorhaving a direction.

Here, the change of the dot movement, density or shape due to thelanding interference may be caused by the function including a jettingtime difference between the dots as well as the inter-dot distance. Thatis, the function f(*) may be a function using the inter-dot distance andthe jetting time difference between the dots.

In FIG. 11, since the simulation image is disposed by reflecting therecording characteristics such as the dot diameter, the dot shape, thedot forming position shift and the landing interference, the simulationimage needs to have resolution higher than that of the halftone imagedata. For example, in a case where the resolution of the halftone imagedata is 1200 dots per inch [dpi] in both the main scanning direction andthe sub scanning direction, the size of each cell is about 21micrometers [μm]×21 micrometers [μm]. However, if the dot formingposition shift is about 3 micrometers [μm], the simulation image needsto have the resolution of 8400 dots per inch [dpi] which is at leastseven times as large as the resolution of the halftone image data.However, after the dots are arranged on a high-resolution simulationimage once, smoothing is performed on the high-resolution simulationimage, and the high-resolution simulation image is converted into alow-resolution simulation image through smoothing. Thus, it is possibleto reduce memory capacity required for the simulation image. That is,since the high-resolution simulation image is needed only near a regionwhere the dots are arranged and the entire simulation image ismaintained with only low resolution, it is possible to reduce the memorycapacity.

When the simulation image is generated in step S26 of FIG. 10, in a casewhere the printing device 24 is a printing system in which each printingelement is independently present over a wide range in a width directionof the printing medium as in the single path printer, not the individualdot density, dot diameter and dot shape of each printing element but theaverage values of the dot densities, dot diameters and dot shapes ofeach printing element for each ink kind may be used.

Subsequently, the image quality of the simulation image generated instep S26 is evaluated (step S28 of FIG. 10).

The image quality evaluation is performed by calculating at least oneevaluation value of a value acquired by applying a low-pass filter suchas a Gaussian filter or a visual transfer function (VTF) representinghuman visual sensitivity to the simulation image, performing frequencyconversion and performing integral calculus, root mean square (RMS)granularity, or an error or a standard deviation with the input image.The value calculated in the image quality evaluation step of step S28 isstored as an “image quality evaluation value” in the memory.

Here, in a case where the tolerance design to the system error isperformed, the generation (step S26) of the simulation image asdescribed above and the calculation (step S28) of the image qualityevaluation value are performed by applying at least one error of apredetermined dot density, a dot diameter, a dot shape, a dot formingposition shift or non-jetting to the dots of the pixels belonging to thesame condition as at least one condition of the printing order, the pathor the timing of the dot-ON pixels corresponding to the currentthreshold value of the halftone processing result.

In a case where the tolerance design is performed such that the streaksare generated as well as the deterioration in granularity as thetolerance to the system error, a value acquired by performingone-dimensional frequency conversion and integral calculus, or an erroror a standard deviation with respect to the value of the integral of theinput image in the main scanning direction is calculated as a streakevaluation value by applying the error to the simulation image andperforming integral calculus on the simulation image in the mainscanning direction after the low-pass filter or VTF is applied. As themethod of calculating a quantitative evaluation value of the granularityor streaks, the known method described in JP2006-67423A orJP2007-172512A may be used.

In the present example, the image quality evaluation value is calculatedby the following equation, and the acquired value is retained.Image quality evaluation value=granularity evaluation value [systemerror absence]+α×{granularity evaluation value [system errorpresence(+predetermined amount)]+granularity evaluation value [systemerror presence(−predetermined amount)}+β×{streak evaluation value[system error presence(+predetermined amount)]+streak evaluation value[system error presence(−predetermined amount)]}  Expression (1)

The granularity evaluation value [system error absence] in thecalculation expression of the image quality evaluation value is agranularity evaluation value calculated from a simulation image to whicha system error corresponding to a variation component of thecharacteristic parameter is not added. The granularity evaluation value[system error presence (+predetermined amount)] is a granularityevaluation value calculated from a simulation image to which a plus(positive) predetermined amount as the system error is added. Thegranularity evaluation value [system error presence(−predeterminedamount) is a granularity evaluation value calculated from a simulationimage to which a minus (negative) predetermined amount as the systemerror is added. The streak evaluation value [system errorpresence(+predetermined amount) is a streak evaluation value calculatedfrom the simulation image to which a plus (positive) predeterminedamount as the system error is added. The streak evaluation value [systemerror presence(−predetermined amount) is a streak evaluation valuecalculated from a simulation image to which a minus (negative)predetermined amount as the system error is added. The coefficients αand β are evaluation parameters, the coefficient α is a granularityevaluation parameter, and the coefficient β is a streak evaluationparameter. In a case where there is an attempt to increase the toleranceto the system error, α or β is set to be a larger value. Particularly,in a case where there is an attempt to make the “streaks” inconspicuousas well as the granularity, the value of β is increased. Thepredetermined amount of an addition error, the kind of the additionerror (density, dot diameter, dot shape, dot forming position shift,non-jetting, or landing interference) and the coefficients α and β asthe evaluation parameters are determined depending on the priority ofthe tolerance to the system error described above.

As the predetermined amount of the addition error, the standarddeviation σ of each item such as the dot densities, the dot diameters,or the dot forming position shifts may be used. As the predeterminedamount of the addition error, at least one of the standard deviation ofthe dot densities, the standard deviation of the dot diameters, thestandard deviation of the dot shapes or the standard deviation of thedot forming position shifts may be used, and an appropriate combinationthereof may be used.

The image quality evaluation value in step S28 of FIG. 10 is calculated,and the halftone parameter is updated in a case where the image qualityevaluation value is enhanced (step S30). In step S32, it is determinedwhether or not the steps of step S22 to step S30 are repeatedlyperformed the predetermined number of times. The “predetermined numberof times” of step S32 in the dither method is the number of all pixelsof candidates corresponding to the threshold value.

If the step is performed the predetermined number of times and the stepis not completed in the determination of step S32, the step returns tostep S22, and the steps of step S22 to step S30 are repeated. In thedetermination of step S32, if the step performed the predeterminednumber of times is completed, the step is ended.

<Case of Error Diffusion Method>

An example in which the flowchart of FIG. 10 is applied to thegenerating of the halftone parameter in the error diffusion method willbe described. In the error diffusion method, the halftone parameterindicates the setting of the size of the error diffusion matrix, thediffusion coefficient and the applied gradation section of each errordiffusion matrix. Here, in order to simplify the description, it isassumed that one kind of common size is used as the size of the errordiffusion matrix.

The flowchart of FIG. 10 is repeated for all the applied gradationsections, and thus, the diffusion coefficient of the error diffusionmatrix of each applied gradation section is determined.

For example, the applied gradation section of the error diffusion matrixcan be divided into five levels of 0-50, 51-100, 101-150, 151-200, and201-255 in the case of an 8-bit gradation. The dividing method of theapplied gradation sections may be performed by various determiningmethods, and the added gradation section may be equally divided into mlevels as an integer m of 2 or more or may be divided in arbitraryunequal gradation regions.

In a certain gradation section, the average value of the evaluationvalues of each gradation is used as the image quality evaluation valueby temporarily setting the diffusion coefficient of the error diffusionmatrix added to the gradation section (step S22), performing thehalftone process on the input image (single-gradation uniform image) ofeach gradation in the gradation section (step S24 of FIG. 10),generating the simulation image (step S26) and the calculating the imagequality evaluation value (step S28).

When the halftone parameter is temporarily set in step S22, it isassumed that the initial value of the diffusion coefficient of the errordiffusion matrix is 1/matrix size. When the temporal setting is repeatedthe predetermined number of items, in the temporal setting of the errordiffusion matrix coefficient after the second temporal setting (stepS22), the temporal setting is performed by adding “±random numbers in apredetermined range” to the respective coefficients of the best errordiffusion matrix and standardizing the summation of coefficients to be“1”.

It is preferable that a diffusion coefficient of an error diffusionmatrix of an adjacent gradation section which has been already optimizedis used as an initial value of a diffusion coefficient related to anerror diffusion matrix of an adjacent gradation section.

The simulation image of step S26 is generated as in the dither method.The image quality evaluation (step S28) is performed as in the dithermethod. However, in a case where the tolerance design to the systemerror is performed, the simulation image is generated by performing theerror addition to the dots of the pixels belonging to the printingorder, the path or the timing, the granularity or streak evaluationvalues are calculated, and the summation thereof is used as the“evaluation value”. For example, the granularity evaluation value in thesystem error presence is represented by the following expression.Granularity [system error presence]=[granularity evaluation value[system error presence (addition of “+predetermined amount” error tofirst group)]+granularity evaluation value [system error presence(addition of “+predetermined amount” error to second group)]+ . . .+granularity [system error presence (addition of “−predetermined amount”error to first group)]+granularity evaluation value [system errorpresence (addition of “−predetermined amount” error to second group)+ .. . ]  Expression (2)

Here, the group classification such as the first group and the secondgroup indicates a pixel group belonging to the same condition as atleast one condition of the printing order, the path or the timing. Forexample, in the case of a drawing mode in which drawing along 8 inwardand outward paths is completed, the group may be sequentially classifiedsuch that a pixel group recorded along a first path is a first group anda pixel group recorded along a second path is a second group, and apixel group recorded in along eight path may be an eighth group.

The “predetermined amount” of the error added to the pixels belonging toeach classified group may have the same value between the groups, or mayhave different values for each group. The “+predetermined amount” andthe “−predetermined amount” may have the same absolute value, or mayhave different absolute values.

FIG. 12A shows that the jetting order in a drawing mode in which drawingis performed along 8 scanning paths with predetermined recordingresolution is represented by a path number. FIG. 12B is a conceptualdiagram in a case where a predetermined amount of error is added to thedots of the pixels of the first path in a case where the drawing isperformed in the drawing mode shown in FIG. 12A. In FIG. 12B, the errorof the dot forming position shift in the X direction is added to thedots of each pixel groups jetted along the first path. The error may beadded to the pixel group of another path number.

FIG. 13 shows that the error in which the dot diameter is decreased by apredetermined amount is added to the dots of the pixels of the thirdpath in a case where the drawing is performed in the drawing mode shownin FIG. 12A. The dot diameter depicted by a broken line of FIG. 13indicates an average dot diameter having no error.

<Another Example of Dither Method>

The dither method is not limited to the flowchart described in FIG. 10,and a void-and-cluster method may be used. FIG. 14 is a flowchart of thevoid-and-cluster method.

Initially, a halftone initial image is prepared (step S42). A method ofgenerating the halftone initial image follows the void-and-clustermethod. That is, in an energy image acquired by applying a filter to asimulation image having a specific gradation, the initial image isgenerated by regarding pixels having a maximum energy value as clusterpixels in which dots are dense, regarding minimum-energy pixels as voidpixels in which dots are sparse and repeatedly exchanging the clusterpixels and the void pixels. For example, an initial image having agradation value “128” in image data expressed by gradations from 0 to255 is generated using a gradation value which is about 50% of a maximumdensity as the specific gradation.

Subsequently, a simulation image is generated from the halftone image byusing the characteristic parameters related to the printing system (stepS44). The method of generating the simulation image is the same as thatin the example described in FIG. 11. A filter is applied to thesimulation image generated in step S44, threshold values are set to theminimum-energy pixels (that is, void pixels) of pixels of the halftoneimage to which dots are not set, and dots are set to the void pixels ofthe halftone image (step S46). For example, a Gaussian filter is used asthe filter used when the filter is applied.

In step S48, it is determined whether or not the setting (that is, thesetting of the dots) of the threshold values to all the gradations iscompleted, and if the setting is not completed, the step returns to stepS44, and the steps of steps S44 and S46 are repeated. That is, in step46, the simulation image is generated from the halftone image to whichdots are newly added (step S44), and the energy image acquired byapplying the filter to the simulation image is generated and thethreshold values are set to the minimum-energy pixels (step S46).

In step S48, if the step on all the gradations is completed, the step ofFIG. 14 is ended.

The flowchart shown in FIG. 14 is the process in a direction in whichthe threshold values are increased from the initial image, but a methodin which the threshold values (that is, gradation values) are decreasedfrom the initial image also follows the void-and-cluster method. Thatis, a process of setting the threshold values to the cluster pixelsamong the pixels to which the dots are set by regarding themaximum-energy pixels of the energy image acquired by applying thefilter to the simulation image as the cluster pixels in which the dotare dense, a process of generating the simulation image by removing thedots of the pixels, a process of setting the threshold values byapplying the filter, and a process of removing the dots are sequentiallyrepeated. For example, a Gaussian filter is used as the filter used whenthe filter is applied.

Similarly to the example described in FIG. 10, in a case where thetolerance design to the system error is performed, the simulation imageis generated by adding at least one kind of error of the error of thepredetermined amount of dot density, the error of the dot diameter, theerror of the dot shape, the error of the dot forming position shift orthe error of the non-jetting to the dots of the pixels belonging to thesame condition as at least one condition of the printing order, the pathor the timing of the pixels corresponding to the current threshold value(step S44), and the filter is applied (step S46).

In a case where the tolerance design to the streaks is performed,one-dimensional energy (that is, streak energy) is calculated as streakenergy by adding the predetermined amount of error to the simulationimage, applying the filter to the simulation image, and performingintegral calculus on the simulation image in the main scanningdirection. As the energy of the entire print image, the pixels whichhave a minimum image evaluation value to be represented below andinclude a streak energy component are searched.Image evaluation value=energy [system error absence]+α×{energy [systemerror presence(+predetermined amount)]+energy [system errorpresence(−predetermined amount)]+β×{streak energy [system errorpresence(+predetermined amount)]+streak energy [system errorpresence(−predetermined amount)]}  Expression (3)

Through the method described in FIG. 10 or 14, the halftone parameter ofthe dither method or the error diffusion method is determined, and thehalftone processing rule specified by the combination of the halftonealgorithm and the halftone parameter. By doing this, the multiple kindsof halftone processing rules are generated.

<Halftone Selection Chart>

In the printing system 10 according to the present embodiment, thehalftone selection chart is output in order to provide determinationinformation when one kind of halftone processing rule used in printingis selected from the multiple kinds of halftone processing rulesgenerated by the image processing device 20 (step S16 of FIG. 4).

For example, as the halftone selection chart, a chart including agradation patch acquired by arranging a primary color such as cyan,magenta or yellow, a secondary color such as red, green or blue, atertiary color or a quaternary color in a predetermined gradation levelmay be used. The halftone selection chart may include a gradation imageacquired by continuously changing a gradation value instead of theacquired gradation patch to a patch, which is acquired by discretelychanging a gradation value in the predetermined gradation level for eachcolor, or by combining these patches.

The halftone selection chart may include a gradation image or a patchhaving a uniform density of a predetermined gradation according to aspecial color such as sky blue or pale orange. As the kind of the“special color”, various colors may be set. The sky blue or the paleorange are examples of colors in which the granularity becomes aparticularly sensitive issue in the printed material. As stated above,the particularly important color in the printed material is set as the“special color”, and may be included in the image of the halftoneselection chart.

The halftone selection chart is a chart capable of being used asdetermination information when an appropriate halftone process isselected by the user through the comparison of the qualities of therespective halftone processes, from the results of the halftoneprocesses represented in the chart.

In order to facilitate the comparison of the qualities of the multiplekinds of halftone processes, it is preferable that a halftone selectionchart in which the processing results of the multiple kinds of halftoneprocesses are provided on one printing medium is generated.

FIG. 15 is a schematic diagram showing an example of the halftoneselection chart. In FIG. 15, an example of a halftone selection chart150 printed by arranging the respective processing rules of the two ormore kinds of halftone processing rules on one printing medium 101 isshown.

A chart region shown on the left side of FIG. 15 is a chart thatrepresents the processing result of a first halftone processing rule(referred to as “Halftone 1”), and a chart region shown on the rightside is a chart that represents the processing result of a secondhalftone processing rule (referred to as “Halftone 2”).

In the halftone selection chart 150 of the present example, as for therespective halftone processes of the two or more kinds of halftoneprocessing rules, a total of 32 primary color patches 151 and 152acquired by dividing a gradation region having gradation values from 0to 255 into 16 levels of “16” notches are arranged for the respectiveprimary colors of C, M, Y and K.

For the sake of convenience in the illustration, FIG. 15 shows that someof the gradation levels are omitted and the number of patches isreduced. However, the primary color patches 151 and 152 corresponding tothe respective gradation values of 16, 32, 48, 64, 80, 96, 112, 128,144, 160, 176, 192, 208, 224, 240 and 255 are recorded for therespective colors of CMYK. Reference numeral 151 denotes primary colorpatches according to the processing result of the first halftoneprocessing rule, and reference numeral 152 denotes primary color patchesaccording to the processing result of the second halftone processingrule.

The halftone selection chart 150 includes gradation images 161 and 162of the respective colors, sky blue patches 171 and 172 according to thea predetermined gradation of sky blue, and pale orange patches 181 and182 according to a predetermined gradation of pale orange in addition tothe arrangement of the primary color patches 151 and 152 of therespective colors of CMYK. Reference numeral 161 denotes gradationimages according to the processing result of the first halftoneprocessing rule, and reference numeral 162 denotes gradation imagesaccording to the processing result of the second halftone processingrule. The gradation images 161 and 162 are image regions of a shadedimage acquired by continuously changing a gradation value in a range ofa gradation region from a minimum gradation value to a maximum gradationvalue for the primary colors of the respective colors of CMYK.

Reference numeral 171 denotes sky blue patches according to theprocessing result of the first halftone processing rules, and referencenumeral 172 denotes sky blue patches according to the processing resultof the second halftone processing rule. Reference numeral 181 denotespale orange patches according to the processing result of the firsthalftone processing rule, and reference numeral 182 denotes pale orangepatches according to the processing result of the second halftoneprocessing rule.

Information items related to system cost, ink cost and processing timefor each halftone processing rule are printed on the halftone selectionchart 150.

Although not shown in FIG. 15, information items indicating granularityevaluation value and/or streak evaluation value in association with thepatches may be printed for some or all of the primary color patches 151and 152. As a method of printing the information items in associationwith the patches, there are an aspect in which the information items areprinted so as to overlap the patches, or an aspect in which theinformation items is printed close to the patches.

The same is true of the sky blue patches 171 and 172 or the pale orangepatches 181 and 182, and the information items indicating granularityevaluation value and/or streak evaluation value in association with thepatches may be similarly printed for some or all of the patches (171,172, 181 and 182).

The user may compare the chart of the processing result according to thefirst halftone processing rule and the chart of the processing resultaccording to the second halftone processing rule, and may select apreferable halftone processing rule.

The primary color patches 151 and 152, the gradation images 161 and 162,the sky blue patches 171 and 172 and the pale orange patches 181 and 182of the halftone selection chart 150 shown in FIG. 15 are image regionsfor comparing and evaluating the quality of the halftone process, andcorrespond to one example of a “comparison and evaluation image region”.

The chart is not limited to the form of the halftone selection chart 150illustrated in FIG. 15, and various forms of charts may be used. Agradation image of another color such as the secondary color, thetertiary color or the quaternary color may be formed instead of thegradation images to the gradation images 161 and 162 of the primarycolors illustrated in FIG. 15 or by a combination thereof. Various kindsof colors or layouts of patches or gradation images as the comparisonand evaluation image region may be used.

When the halftone selection chart is output, in order to evaluate thetolerance (deterioration in granularity or suppression of streakoccurrence) to the system error of the halftone process, the same chartmay be disposed on the entire surface of the printing medium in adrawing executable range, or the content of the same chart may be outputover multiple pages. The configuration in which the same chart isdisposed on the entire surface of the printing medium in the drawingexecutable range is beneficial in a case where the tolerance to thesystem error depending on the printing position (printing place) withinthe drawing executable range is evaluated. The configuration in whichthe content of the same chart is output over multiple pages isbeneficial in a case where the tolerance to the temporal system error isevaluated. The “content of the same chart” is one example of “an imageof the same halftone processing result”. The configuration in which thesame chart is output so as to be disposed on the entire surface of theprinting medium in the drawing executable range corresponds to oneexample of a configuration in which “the image of the same halftoneprocessing result is output in different position on the printing mediummultiple times”. The configuration in which the content of the samechart is output over multiple pages corresponds to one example of aconfiguration in which the image of the same halftone process is outputin different printing timings multiple times.

In the configuration in which the same chart is output over multiplepages, when the same chart is continuously output while temporallyshifting the chart, a continuous chart output may be performed on themultiple kinds of halftone processes by switching the halftone process.In this case, it is preferable that the printing place (printingposition on the printing medium) of the processing result of the samehalftone process is fixed. In a case where the chart of the processingresult of the same halftone process is output over multiple pages, thechart is printed in the same place of each printing medium, and thus,the influence of the system error depending on the place can beexcluded.

In the configuration in which the same chart is output multiple timeswhile spatially shifting the chart, the halftone processing resultsadjacent to each other on one printing medium may be processing resultsof different kinds of halftone processes. In the configuration in whichthe same chart is output multiple times while spatially shifting thechart, the same halftone processing results may be output on the sameone printing medium. Accordingly, the influence of the system error withtime can be excluded.

As described in FIG. 15, information beneficial to the determination orselection performed by the user is not limited to the image indicatingthe processing result of the halftone process, and at least oneinformation item of the quantitative evaluation value of the granularityor streak, the system cost, the ink cost, the halftone generating timeor the halftone processing time may be printed on the printed materialof the halftone selection chart. For example, the “system cost” isindicated as cost an additional option for functional enhancementrequired to realize the system specification necessary to be performedwithin a required halftone processing time. As for the “ink cost”, sincea slight difference in the usage amount of ink is generated depending onthe kind of the halftone, ink cost is calculated from the ink usageamount for each kind of halftone in a case where the same image contentis printed over a predetermined sheet of page, and informationindicating the ink cost is presented. At least one of the system cost orthe ink cost corresponds to “cost”.

At least one information item of the quantitative evaluation value ofthe granularity or streak, the system cost, the ink cost, the halftonegenerating time or the halftone processing time related to theprocessing result of the halftone process may be displayed on the screenof the user interface instead of the configuration in which the halftoneselection chart is printed and presented at the time of outputting or bya combination thereof. The configuration in which the information of theevaluation value related to such quantitative evaluation together withthe halftone selection chart is printed, or the configuration in whichthe screen of the user interface is displayed corresponds to one exampleof “information presentation means”. That is, the display device 32 (seeFIGS. 2 and 3) of the image processing device 20 may function as the“information presentation means”.

As for the quantitative evaluation value of the granularity or streak,the simulation image may be generated from the halftone processingresult of the halftone selection chart by the above-described method andthe granularity evaluation value or the streak evaluation value may becalculated. Alternatively, the output result of the halftone selectionchart may be read by the image reading device 26 such as the in-linescanner, and the granularity evaluation value or the streak evaluationvalue may be calculated from the read image.

In order to evaluate the tolerance to the system error, the generationof the simulation image related to the halftone selection chart includesthe generation of the simulation image by adding a predetermined amountof error to the dots of the pixel group belonging to the same conditionas at least one condition of the printing order, the path or the timing.

In a case where the quantitative evaluation value of the granularity orstreak is calculated from the simulation image, the calculated value maybe printed on the printed material of the halftone selection chart.

Meanwhile, in a case where the output result of the halftone selectionchart is read and the quantitative evaluation value of the granularityor streak is calculated from the read image, the calculation result maybe displayed on the screen of the user interface. The user can select anappropriate halftone process by referring to the quantitative evaluationvalue displayed on the screen of the user interface and checking theprinted material of the halftone selection chart.

As another method, in a case where the output result of the halftoneselection chart is read and the quantitative evaluation value of thegranularity or streak is calculated from the read image, the calculationresult may be additionally printed on the read halftone selection chart.Alternatively, after the read halftone selection chart is output, whenthe same halftone selection chart is output, the already calculatedquantitative evaluation value of the granularity or streak may beprinted.

In a case where the information of the quantitative evaluation value ofthe granularity or streak is presented, an aspect in which a portion ofthe patch in which a difference in evaluation value or a change inevaluation value necessary to alert the user is generated is highlightedon the screen or the printed material is preferable.

For example, in a case where the halftone selection chart is output overmultiple pages with a temporal difference between the printing timingsand the change with a change in time is checked, the notification that achange in quantitative evaluation value calculated from the read imageof the halftone selection chart exceeds an allowable range and is largemay be highlighted so as to alert the user. In this case, the history ofthe quantitative evaluation value is stored in the memory, and adifferentiated display or another highlight display is performed in acase where the change amount of the quantitative evaluation valueexceeds the allowable range.

In addition to checking the temporal system error, that is, instabilityof the system for time using the halftone selection chart, it ispossible to check the system error depending on the printing position(place) on the printing medium, that is, the instability of the systemfor the space (place) by using the halftone selection chart. In thiscase, the notification that a difference in quantitative evaluationvalue exceeds the allowable range and is large due to a difference inplace may be highlighted so as to alert the user.

After one halftone processing rule is selected by the automaticselection of the system or the selection operation of the user, aplurality of other halftone processing rules of which the prioritybalances of the first classification (a) and the second classification(b) of the requirements approximate the selected halftone processingrule may be further generated, the image quality evaluation value or thetotal evaluation value may be calculated based on the priority parameteror the halftone selection chart may be output, and the system or theuser may select an optimum halftone processing rule and the calculatedvalues or output halftone selection chart. In a case where the systemautomatically selects the halftone process, the halftone processing rulemay be repeatedly generated until the image quality evaluation value orthe total evaluation value is equal to or greater than a predeterminedthreshold value.

<Method of Generating Halftone Selection Chart Using DBS Method>

FIG. 16 is a flowchart showing a procedure of generating the halftoneimage of the halftone selection chart using the DBS method. In the DBSmethod, the halftone image of the halftone selection chart is acquiredbased on the already determined halftone parameter according to theflowchart of FIG. 16.

Initially, the initial halftone image is prepared (step S52). Theinitial halftone image is separately generated by performing a ditherprocess using the halftone processing rule of the dither methodgenerated in step S14 of FIG. 4 or a simply generated dither mask on thehalftone selection chart.

Subsequently, a process of replacing the dots of the halftone image isperformed (step S54 of FIG. 16). The simulation images are generatedusing the characteristic parameters related to the characteristics ofthe printing system before and after the dots are replaced (step S56).The image quality is evaluated for the generated simulation images (stepS58), and the halftone image is updated in a case where the evaluationvalue is enhanced before and after the dots are replaced (step S60). Theimage quality evaluation value calculated when the image quality isevaluated in step S58 is acquired by applying the low-pass filter suchas the Gaussian filter or the visual transfer function (VTF)representing the human visual sensitivity and calculating an error(difference) between the input image and the simulation image.

The steps from step S54 to step S60 are repeated by repeatedly replacingdots a predetermined number of times according to the previously set“pixel updating number of times”.

In step S62, it is determined whether or not the process of replacingthe dots the predetermined number of times is completed. In a case wherethe process of replacing the dots the predetermined number of times isnot completed, the step returns to step S54, and the steps from step S54to step S60 are repeated. In step S62, in a case where it is determinedthat the process of replacing the dots the predetermined number of timesis completed, this process is ended.

<Means for Compensating for Image Quality Deterioration Due to Influenceof Landing Interference>

It has been described that it is assumed that the simulation imageincluding the landing interference is generated in order to acquire afavorable halftone processing result by adding the influence of thelanding interference in the generation of the respective halftoneparameters of the dither method and the error diffusion methodrepresented by the flowcharts of FIGS. 10 and 14 or the halftone processof the direct binary search (DBS) method represented by the flowchart ofFIG. 16. However, since an excessive time necessary to simulate thelanding interference and simulation accuracy are problems, it ispreferable that image quality deterioration due to the influence of thelanding interference can be compensated by a simple method withoutperforming the simulation. From such a viewpoint, a configuration inwhich means for compensating for the image quality deterioration due tothe landing interference when the dots are in contact is provided is oneof a desirable form.

For example, in order to compensate for granularity deterioration due tothe influence of the landing interference, the moving direction ormoving amount may be estimated for the dot of each pixel based on thekind, contact direction or contact amount of surrounding dots, each dotmay be classified as a small group having the same moving directionand/or same moving amount based on the moving direction and/or movingamount, and the halftone parameter may be generated or the halftoneprocess may be performed while favorably maintaining the granularity ofeach small group. In order to compensate for streak, unevennessoccurrence and granularity deterioration due to the landing interferencein a case where there are the errors of the dot diameter, the dot shape,the dot forming position shift and the non-jetting, at least one errorof a predetermined dot diameter, a dot shape, a dot forming positionshift or non-jetting may be added to the dots of the pixel groupbelonging to the same printing order, path or timing, the movingdirection or moving amount may be estimated for the dot of each pixel ofthe group based on the kind, contact direction or contact amount ofsurrounding dots, each dot may be classified as a small group having thesame moving direction and/or moving amount based on the moving directionand/or moving amount, and the halftone parameter may be generated or thehalftone process may be performed while favorably maintaining thegranularity of each small group.

Alternatively, in order to compensate for the streak, unevennessoccurrence and granularity deterioration due to the landing interferencein a case where there is at least one error of the dot diameter, the dotshape, the dot forming position shift or the non-jetting, even though atleast one error of a predetermined dot diameter, a dot shape, a dotforming position shift or non-jetting is added to the dots of the pixelgroup belonging to the same printing order, path or timing, thegeneration of the halftone parameter or the halftone process may beperformed such that a change in contact state of the dots of the groupwith the surrounding dots is decreased.

<Significance of What Halftone Selection Chart is Output>

The halftone selection chart has at least one significance of a firstsignificance of what the halftone selection chart is output to comparethe processing results of the two or more kinds of halftone processingrules or a second significance of what the halftone selection chart isoutput to check the instability of the system. The chart configurationin which the processing results of the two or more kinds of halftoneprocessing rules are provided on one printing medium 101 is beneficialto the first significance. Meanwhile, in a case where the secondsignificance is paid attention to, the processing results of the two ormore kinds of halftone processing rules are not necessarily provided onone printing medium 101. In order to check the instability of the systemdepending on the place or check the instability of the system for thetime, the chart form in which only the processing rule of one kind ofhalftone processing rule is recorded on the printing medium 101 may beused.

<Generation of Two or More Kinds of Halftone Processing Rules andComparison of these Processing Results>

It has been described in the present embodiment that at least two kindsof halftone processing rules are generated, and more preferably, two ormore halftone processing rules are generated.

FIG. 17 is a graph showing qualitative tendencies of various halftoneprocessing rules in a case where a horizontal axis represents the imagequality and a vertical axis represents the system cost or the halftoneprocessing time. If the comparison is relatively performed on thehalftone algorithms of the dither method, the error diffusion method andthe DBS method, the image quality becomes higher in sequential order ofthe dither method, the error diffusion method and the DBS method, andthe system cost or the halftone processing time becomes higher or longerin sequential order of the dither method, the error diffusion method andthe DBS method. However, in all the dither method, the error diffusionmethod and the DBS method, the balance between the image quality and thesystem cost or the halftone processing time can be changed depending onthe setting of the halftone parameter.

Various kinds of halftone processes of which the balances of therequirements are different may be set. However, in the example shown inFIG. 17, a total of 9 kinds of settings in which the level of the “imagequality” is divided into 3 levels of low/medium/high are performed forthe dither method, the error diffusion method and the DBS method. InFIG. 17, D1, D2 and D3 represent 3 kinds of settings in the dithermethod, ED1, ED2 and ED3 represent 3 kinds of settings in the errordiffusion method, and DBS1, DBS2 and DBS3 represent 3 kinds of settingsin the DBS method.

Unlike the advantages and disadvantages of each requirement depending onthe halftone algorithm described in FIG. 17, if the granularity isimproved using one parameter irrespective of the halftone algorithm,there is a tendency for the tolerance to the instability of the systemto be deteriorated, as shown in FIG. 18.

In FIG. 18, a horizontal axis represents the granularity, and a verticalaxis represents the tolerance to the instability of the system. In FIG.18, as the tolerance to the instability of the system, there are boththe tolerance of the granularity and the tolerance of the streaks, butthere is the same qualitative tendency in both these tolerances. In FIG.18, only the tolerance of the granularity is illustrated. That is, asshown in FIG. 18, there is a tendency for the tolerance to theinstability of the system to be deteriorated and the tolerance of thestreaks to be deteriorated if the granularity is increased. In contrast,there is the relation that the tolerance to the instability of thesystem is improved and the tolerance of the streaks is also improved ifthe granularity is sacrificed.

For example, as the setting example of the tolerance to the instabilityof the system, it is considered that 3 kinds of settings in which thelevel of the tolerance is divided into 3 levels of high/medium/low areperformed. In FIG. 18, T1, T2 and T3 represent 3 kinds of settingsperformed on the tolerance to the instability of the system.

Two or more kinds of halftone processing rules of which the balances ofthe plurality of requirements for the halftone process are different aregenerated based on the qualitative tendency described in FIGS. 17 and18. For example, a total of 27 kinds of halftone processing rules may begenerated as a default by combining 9 kinds of settings described inFIG. 17 with 3 kinds of settings related to the tolerance of thegranularity described in FIG. 18.

The halftone selection charts according to the processing results of 27kinds of halftone processing rules may be output, and one halftoneprocessing rule may be selected from these charts by the user.

As another method, the user may designate the setting of the priorityfor the requirement, may generate two kinds or several kinds of halftoneprocessing rules which approximate the setting of the priority, maypreviously reflect the intension of the user, and may narrow thepresentation range of the kind of the halftone process.

For example, the kind of the halftone algorithm may be previouslyrestricted and the halftone processing rule may be generated such thatthe DBS method or the error diffusion method is used in a case where thesetting in which the image quality is important is designated, the errordiffusion method is used in a case where the setting in which the imagequality and the cost balance are important is designated, and the dithermethod is used in a case where the setting in which the cost isimportant is designated.

A quantitative requirement value as a target is previously estimated tosome extent for the halftone processing time or the cost of therequirements in many cases. That is, in order to meet the requirementssuch as productivity, the user can previously set a target value to thehalftone processing time or the cost in many cases.

Accordingly, a plurality of halftone processing rules may be selectedfrom 27 kinds of halftone processing rules within a range that satisfiesthe requirements (target value) of the user, and may be actually outputas the halftone selection chart.

<Selection of Halftone Process>

The method of selecting one halftone processing rule from the two ormore kinds of halftone processing rules is not limited to a form inwhich the user checks the chart output of the halftone selection chartand selects any one halftone process, and the system may automaticallyselect one halftone process.

In this case, the system previously retains the priority parameters forthe plurality of requirements. For example, there is the image quality,the system cost or the halftone generating time as the firstclassification (a) of the requirement, and there is the granularity orthe tolerance to the system error as the second classification (b) ofthe requirement. The system previously retains the following parametersA, B, C, D, p, q and r, and the total evaluation value is calculated bythe following expression.Total evaluation value=A×image quality evaluation value+B×systemcost+C×halftone generating time+D×halftone processing timeImage quality evaluation value=p×granularity evaluation value [systemerror absence]+q×{granularity evaluation value [system error presence(addition of “+predetermined amount” error to first group)]+granularityevaluation value [system error presence (addition of “+predeterminedamount” error to second group)]+ . . . +granularity evaluation value[system error presence (addition of “−predetermined amount” error tofirst group)]+granularity evaluation value [system error presence(addition of “−predetermined amount” error to second group)]+ . . .}+r×{streak evaluation value [system error presence (addition of“+predetermined amount” error to first group)]+streak evaluation value[system error presence (addition of “+predetermined amount” error tosecond group)]+ . . . +streak evaluation value [system error presence(addition of “−predetermined amount” error to first group)]+streakevaluation value [system error presence (addition of “−predeterminedamount” error to second group)]+ . . . }  Expression (4)

Here, in order to acquire the image quality evaluation value, thesimulation image is generated from the halftone processing result of thehalftone selection chart by the above-describe method, the granularityevaluation values or the streak evaluation values are calculated, thevalues of the evaluation are appropriately averaged values for eachcolor, each gradation, sky blue or pale orange.

The granularity evaluation values or the streak evaluation values may beaveraged or may not be average for the ink kind. In order to acquire thegranularity or streak evaluation values for the system error, thegeneration of the simulation image includes the generation of thesimulation image by respectively adding the error to the dots of thepixel group belonging to the same condition as the printing order, thepath or the timing.

A simulation condition applied when the halftone process generation ofgenerating the two or more kinds of halftone processing rules isperformed as a previous stage does not necessarily coincide with asimulation condition applied when the simulation image qualityevaluation in the halftone selection of selecting one halftoneprocessing rule from the two or more kinds of halftone processing rulesby the user selection or the automatic selection of the system isperformed. For example, the simulation in the halftone processgeneration may be performed in a condition in which the factor of thelanding interference is not included or a condition in which thesimulation is performed in consideration of only the “dot movement” ofthe factor of the landing interference in order to promptly generate thehalftone processing rule, and the simulation in the automatic halftoneselection may be performed including all changes in dot density, dotshape and dot movement due to the landing interference in order toreliably reproduce a reality image if possible. Here, the “halftoneprocess generation” indicates the generation of the halftone parameterin a case where the halftone algorithm is the dither method or the errordiffusion method and the generation of the halftone image in a casewhere the halftone algorithm is the DBS method.

As the predetermined amount of the added error (that is, a predeterminederror amount), an appropriate value may be separately determined, or maybe a standard deviation calculated from the reading result of thecharacteristic parameter acquisition chart.

Alternatively, instead of the calculation of the evaluation value basedon the simulation image, the halftone selection chart output by theprinting device 24 may be read by the image reading device 26, thegranularity evaluation value or the streak evaluation value may becalculated from the read image, the values of the evaluation values maybe appropriately averaged for each color, each gradation, sky blue orpale orange, and the image quality evaluation value may be acquired bythe following expression.Image quality evaluation value=p×granularity evaluation value+r×streakevaluation value

The respective allowable threshold values may be set to the imagequality evaluation value, the system cost, the halftone generating time,the halftone processing time, the granularity evaluation value [systemerror absence], the granularity evaluation value [system error presence]and the streak evaluation value, the halftone processing rules of whichthe value is equal to or greater than the threshold value may beinitially extracted, and an optimum halftone process may be determinedbased on the total evaluation value from the extracted halftoneprocessing rules.

For example, in a case where there is an attempt to determine thehalftone process in which the system cost is as low as possible, thereis a method of acquiring the total evaluation value by initiallyextracting the halftone processes of which the value is equal to orgreater than the allowable threshold value for the image qualityevaluation value, the system cost, the halftone generating time, thehalftone processing time, the granularity evaluation value [system errorabsence], the granularity evaluation value [system error presence] andthe streak evaluation value and setting the priority parameter B to be alarge value.

The total evaluation value is one example of a “determination evaluationvalue”. Real numbers indicating the priorities are respectively set tothe priority parameters A, B, C, D, p, q and r.

After one halftone processing rule is selected by the automaticselection of the system or the selection operation of the user, aplurality of other halftone processing rules of which the prioritybalances of the first classification (a) and the second classification(b) of the requirements approximate the selected halftone processingrule may be further generated, the image quality evaluation value or thetotal evaluation value may be calculated based on the priority parameteror the halftone selection chart may be output, and the system or theuser may select an optimum halftone processing rule and the calculatedvalues or output halftone selection chart. In a case where the systemautomatically selects the halftone process, the halftone processing rulemay be repeatedly generated until the image quality evaluation value orthe total evaluation value is equal to or greater than a predeterminedthreshold value.

<Description Related to Function of Image Processing Device According toSecond Embodiment>

FIG. 19 is a block diagram for describing a function of an imageprocessing device according to a second embodiment. The image processingdevice according to the second embodiment shown in FIG. 19 may be usedinstead of the configuration of the image processing device according tothe first embodiment described in FIG. 3. In FIG. 19, the same orsimilar elements as or to those of the configuration described in FIG. 3will be assigned the same reference numerals, and the descriptionthereof will be omitted.

The halftone process generation unit 58 of the image processing device20 according to the second embodiment shown in FIG. 19 includes aprevious-stage halftone process generation unit 58A, and a halftoneautomatic selection unit 58B. The previous-stage halftone processgeneration unit 58A generates the halftone processing rule that definesthe processing contents of the two or more kinds of halftone processesof which the balances of priority for the plurality of requirementsrequired in the halftone process are different based on thecharacteristic parameters. The halftone automatic selection unit 58Bperforms a process of automatically selecting the kind of the halftoneprocess used in the printing of the printing system 10 from the kinds ofthe halftone processes defined by the two or more kinds of halftoneprocessing rules generated by the previous-stage halftone processgeneration unit 58A based on the priority parameters.

The halftone automatic selection unit 58B corresponds to one example of“halftone automatic selection means”. The halftone automatic selectionunit 58B includes a determination-evaluation-value calculation unit 59as one example of “determination-evaluation-value calculation means”.

The determination-evaluation-value calculation unit 59 is calculationmeans for calculating a determination evaluation value that evaluatesthe adequateness of the halftone process defined by the halftoneprocessing rule generated by the previous-stage halftone processgeneration unit 58A. The determination-evaluation-value calculation unit59 calculates the determination evaluation value based on the priorityparameter retained by the priority parameter retention unit 56. That is,the determination-evaluation-value calculation unit 59 calculates atotal evaluation value which is one example of the determinationevaluation value. The specific example of the total evaluation value isalready described. The halftone automatic selection unit 58Bautomatically selects the kind of the halftone process used in theprinting of the printing system 10 based on the determination evaluationvalue calculated by the determination-evaluation-value calculation unit59.

The priority parameter retention unit 56 stores the priority parametersthat designate the balances of priority related to a plurality ofrequirements. The step of causing the priority parameter retention unit56 to store the priority parameters corresponds to one example of apriority parameter retention step.

The priority parameter is freely input by the user through the inputdevice 34, and thus, the balances of priority can be set and the settingcontent can be changed.

The image processing device 20 includes the image quality evaluationprocessing unit 74 which includes the simulation image generation unit68 and the evaluation value calculation unit 70, and the halftoneprocess generation unit 58 generates the halftone processing rule incooperation with the image quality evaluation processing unit 74. Thesimulation image generation unit 68 corresponds to one example of“simulation image generation means”, and the evaluation valuecalculation unit 70 corresponds to one example of“image-quality-evaluation-value calculation means”.

The image quality evaluation processing unit 74 performs an optimumsearching process in which the evaluation value is enhanced whilerepeatedly performing the generation of the simulation image and thecalculation of the evaluation value of the image quality for thesimulation image. The halftone parameter is determined through theprocess performed by the image quality evaluation processing unit 74.The simulation image generation unit 68 generates the simulation imagein a case where the halftone image acquired by applying the halftoneprocess defined by the halftone processing rule generated by theprevious-stage halftone process generation unit 58A is printed, and theevaluation value calculation unit 70 calculates the image qualityevaluation value from the simulation image generated by the simulationimage generation unit 68. The determination-evaluation-value calculationunit 59 of the halftone automatic selection unit 58B can calculate thedetermination evaluation value by using the image quality evaluationvalue calculated by the image quality evaluation processing unit 74.

The multiple kinds of halftone processing rules generated by theprevious-stage halftone process generation unit 58A are registered inthe halftone-processing-rule storage unit 60.

The image analysis unit 64 shown in FIG. 19 functions as means forcalculating a quantitative evaluation value of the halftone image byanalyzing the read image of the halftone selection chart output from theprinting device 24 in addition to function as means for generating thecharacteristic parameters by analyzing the read image of thecharacteristic parameter acquisition chart. Thedetermination-evaluation-value calculation unit 59 of the halftoneautomatic selection unit 58B may acquire information of at least onequantitative evaluation value of the granularity evaluation value or thestreak evaluation value calculated by the image analysis unit 64 basedon the output result of the halftone selection chart from the imageanalysis unit 64, and may calculate the determination evaluation value.The halftone automatic selection unit 58B may perform a process ofautomatically selecting the optimum halftone processing rule based onthe quantitative evaluation value calculated from the read image of thehalftone selection chart.

FIG. 20 is a flowchart showing a method of generating the halftoneprocessing rule in the printing system including the image processingdevice according to the second embodiment.

In FIG. 20, the steps common to the steps of the flowchart described inFIG. 4 will be assigned the same step numbers, and thus, the descriptionthereof will be omitted. In FIG. 20, the steps from step S10 to step S14are the same as those of the flowchart of FIG. 4.

After the two or more kinds of halftone processing rules are generatedbased on the characteristic parameters in step S14, one kind of halftoneprocessing rule is determined from the two or more kinds of generatedhalftone processing rules based on the priority parameter (step S17).That is, the combination of step S14 and step S17 corresponds to oneexample of a “halftone process generation step”. Step S14 is a previousstage for acquiring one optimum halftone process for the system, and thetwo or more kinds of halftone processing rules are generated. In stepS17, a stepwise process of selecting one kind of optimum halftonepriority parameter from the two or more kinds of halftone processingrules generated in step S14 is performed.

However, when the present invention is implemented, the presentinvention is not necessarily limited to the configuration in which thestep of the stepwise process shown in FIG. 20 is performed. For example,an evaluation function that reflects the setting of the priorityparameter may be defined, and one kind of halftone processing rule maybe generated using an optimum method of searching an optimum solutionwhich maximizes or minimizes the evaluation value as the value of theevaluation function for the combination of the halftone algorithm andthe halftone parameter.

In this case, the multiple kinds of halftone processing rules may begenerated during the calculation process of calculating the optimumsolution, but the halftone processing rule generated as the kind of thehalftone process capable of being ultimately used in the system may beanalyzed to be one kind of halftone processing rule as the optimumsolution.

Even in a case where one halftone processing rule is automaticallyselected (determined) by the system according to the setting of thepriority parameter, the halftone processing rule determined by theautomatic selection may be appropriately changed by the user. It ispreferable that various halftone processing rules generated by the imageprocessing device 20 are registered as a line-up such that the halftoneprocessing rule can be reselected by changing the setting of thepriority parameter by the user operation or the program of the system.

It is preferable that information items of the quantitative evaluationvalue of the granularity or streaks, the halftone generating time, thehalftone processing time and the system cost related to the halftoneprocessing rule are stored in association with the halftone processingrule such that these information items are referred to if necessary.

The image quality evaluation value, the system cost, the halftonegenerating time and the halftone processing time may be calculated foreach color of ink used in the printing device 24, that is, for each inkkind, and a different halftone algorithm and halftone parameter may beselected for each ink kind. Alternatively, the image quality evaluationvalue, the system cost, the halftone generating time and the halftoneprocessing time may be calculated for all colors, and the same commonhalftone algorithm and halftone parameter may be selected for allcolors.

<Another Example of Characteristic Parameter Acquisition Chart>

FIG. 21 is a diagram showing another example of the characteristicparameter acquisition chart. A characteristic parameter acquisitionchart 200 shown in FIG. 21 is an example of the characteristic parameteracquisition chart output by the single path printer.

The characteristic parameter acquisition chart 200 shown in FIG. 21includes single dot patterns 202C, 202M, 202Y and 202K, first continuousdot patterns 204C, 204M, 204Y and 204K, and second continuous dotpatterns 206C, 206M, 206Y and 206K, which are recorded on a printingmedium 201 by nozzles which are printing elements in recording heads ofthe respective colors of cyan, magenta, yellow and black.

The single dot patterns 202C, 202M, 202Y and 202K are discrete dotpatterns in which dots are discretely recorded in an isolation state inwhich the single dot is isolated from another dot. The first continuousdot patterns 204C, 204M, 204Y and 204K and the second continuous dotpatterns 206C, 206M, 206Y and 206K are continuous dot patterns in whichtwo or more dots are recorded so as to be in contact.

The single dot patterns 202C, 202M, 202Y and 202K correspond to thesingle dot patterns 102C, 102M, 102Y and 102K of the characteristicparameter acquisition chart 100 described in FIG. 5. The firstcontinuous dot patterns 204C, 204M, 204Y and 204K of FIG. 21 correspondto The first continuous dot patterns 104C, 104M, 104Y and 104K of thecharacteristic parameter acquisition chart 100 described in FIG. 5, andthe second continuous dot patterns 206C, 206M, 206Y and 206K of FIG. 21correspond to the second continuous dot patterns 106C, 106M, 106Y and106K of the characteristic parameter acquisition chart 100 described inFIG. 5. The first continuous dot patterns 104C, 104M, 104Y and 104K andthe second continuous dot patterns 106C, 106M, 106Y and 106K of FIG. 5in which the plurality of dots in contact with each other are adjacentin the main scanning direction are different from the first continuousdot patterns 204C, 204M, 204Y and 204K and the second continuous dotpatterns 206C, 206M, 206Y and 206K of FIG. 21 in which the plurality ofdots in contact with each other are adjacent in the sub scanningdirection.

In both the single path type and the serial scan type, multiple levelsof continuous dot patterns acquired by changing a jetting timedifference as well as the distance between two dots jetted so as tooverlap in the continuous dot pattern may be similarly formed. In thesingle path type, the transport speed of the printing medium 201 ischanged, and thus, it is possible to change the jetting time differencebetween two dots of the continuous dot pattern.

FIG. 22 is a schematic plan view of a recording head portion of an inkjet printing device as the single path printer used in the outputting ofthe characteristic parameter acquisition chart 200 shown in FIG. 21. InFIG. 22, a longitudinal direction from the top to the bottom is thetransport direction of the printing medium 201. As means (mediumtransport means) for transporting the printing medium 201, various formssuch as a drum transport type, a belt transport type, a nip transporttype, a chain transport type and a palette transport type may beadopted, or an appropriate combination of these types may be adopted.The transport direction of the printing medium 201 is referred to as a“medium transport direction”. In FIG. 22, the medium transport directionis depicted by a white arrow. The medium transport direction correspondsto the “sub scanning direction”. A horizontal direction in FIG. 22, thatis, a direction which is parallel to the paper surface and isperpendicular to the medium transport direction is referred to as a“medium width direction”. The medium width direction corresponds to the“main scanning direction”.

The ink jet printing device as the single path printer shown in FIG. 22includes a cyan recording head 212C that jets a cyan ink, a magentarecording head 212M that jets a magenta ink, a yellow recording head212Y that jets a yellow ink and a black recording head 212K that jets ablack ink.

Each of the cyan recording head 212C, the magenta recording head 212M,the yellow recording head 212Y and the black recording head 212K is aline head having a nozzle array in which a plurality of nozzles isarranged over a length corresponding to the maximum width of an imageforming region in the medium width direction perpendicular to the mediumtransport direction.

The number of nozzles, the arrangement form of nozzles and a nozzledensity of the recording heads (212C, 212M, 212Y and 212K) of therespective colors may be variously designed. A head common to all colorsmay be designed for the recording heads (212C, 212M, 212Y and 212K) ofthe respective colors, or different heads may be designed for therecording heads of some colors or the respective colors.

Here, in order to simplify the illustration, a common structure in whichthe head common to all colors is designed for the recording heads (212C,212M, 212Y and 212K) of the respective recording heads is established,and only 40 nozzles for each of the recording heads (212C, 212M, 212Yand 212K) are shown. In FIG. 22, an example in which the ink jetprinting device uses four inks of CMYK is illustrated, and thecombination of the ink colors and the number of colors is not limited tothe present embodiment. As described in FIG. 6, a light ink, a dense inkor a special color ink may be added if necessary. The arrangement orderof the recording heads of the respective colors is not limited to theexample of FIG. 22.

On an ink jetting surface of the cyan recording head 212C shown in FIG.22, a plurality of ink jetting nozzles 218C is arranged in a regulararrangement pattern in both a row direction along the main scanningdirection and a diagonal column direction which is not parallel andperpendicular to the main scanning direction and has a predeterminedangle. Here, an example of a nozzle arrangement of a matrix arrangementin 4 rows×10 columns in which nozzle arrays in which four nozzles 218Care arranged in the diagonal column direction at a predeterminedinterval are formed in 10 columns in different positions in the mainscanning direction is illustrated.

Such a two-dimensional nozzle arrangement is configured such thatrow-direction nozzle arrays in which 10 nozzles 218C are arranged in aline along the row direction at an equal interval are formed in 4 rowsin different positions in the sub scanning direction. In a case whererow numbers are assigned to the row-direction nozzle arrays in 4 rows inthe order of a first row, a second row, a third row and a fourth rowfrom the bottom to the top of FIG. 22 (that is, from the downstream tothe upstream in the medium width direction), the nozzle positions of thefirst row and the second row are different in the main scanningdirection. Similarly, the nozzle positions in the main scanningdirection are different between the second row and the third row,between the third row and the fourth row, and between the fourth row andthe first row.

If a nozzle interval between the nozzles 218C, which are arranged in aline at an equal interval, in the main scanning direction within therow-direction nozzle array is L_(N), the shift amount of the nozzleposition in the main scanning direction between the first row and thesecond row, between the second row and the third row, between the thirdrow and the fourth row, and between the fourth row and the first row isL_(N)/4 which is a value acquired by dividing L_(N) by the total numberof rows. Such a two-dimensional nozzle arrangement may be considered asa nozzle array in which the respective nozzles 218C are arranged at anequal interval (an interval of “L_(N)/4”) in the main scanningdirection.

The arrangement form of the ink jetting nozzles 218M of the magentarecording head 212M, the arrangement form of the ink jetting nozzles218Y of the yellow recording head 212Y and the arrangement form of theink jetting nozzles 218K of the black recording head 212K are the sameas the nozzle arrangement form of the cyan recording head 212C.

The present embodiment is not limited to the matrix arrangementillustrated in FIG. 22. In general, in the recording head having thetwo-dimensional nozzle arrangement, a projection nozzle array projected(orthogonally projected) such that the respective nozzles in thetwo-dimensional nozzle arrangement are arranged in the medium widthdirection (corresponding to the main scanning direction) may beconsidered to be equivalent to a single-row nozzle array in which thenozzles are arranged at an approximately equal interval with a nozzledensity capable of achieving a recording resolution in the main scanningdirection (medium width direction). The “equal interval” mentionedherein means that a jetting point capable of being recorded in the inkjet printing device are a substantially equal interval. For example, acase where intervals are slightly differentiated in consideration of themovement of the liquid droplets on the medium due to the landinginterference or a manufacturing error included in the concept of the“equal interval”. If the projection nozzle array (referred to as a“substantial nozzle array”.) is considered, the nozzle positions (nozzlenumbers) may be associated with the projection nozzles in the order ofthe arrangement of the projection nozzles arranged in the main scanningdirection. The number of nozzles or the arrangement form of nozzlesconstituting the two-dimensional nozzle arrangement is appropriatelydesigned depending on the recording resolution and a drawing executablewidth.

When the line head is formed, a plurality of short head modules in whicha plurality of nozzles is two-dimensionally arranged is connected, andthus, it is possible to form the line head including a nozzle arrayhaving a required length in the medium width direction.

As shown in FIG. 22, the ink jet printing device that uses the recordingheads (212C, 212M, 212Y and 212K) as the line head including a nozzlearray having a length corresponding to the entire width of the imageforming region of the printing medium 201 can record the image in theimage forming region of the printing medium 201 by transporting theprinting medium 201 at a predetermined speed by medium transport means(not shown), performing jetting from the respective recording heads(212C, 212M, 212Y and 212K) in an appropriate timing according to thetransport of the printing medium 201 and performing an operation (thatis, single sub scanning) of relatively moving the printing medium 201and the respective recording heads (212C, 212M, 212Y and 212K) once inthe medium transport direction.

According to the configuration of FIG. 22, it is possible to form thesingle dot patterns 202C, 202M, 202Y and 202K, the first continuous dotpatterns 204C, 204M, 204Y and 204K and the second continuous dotpatterns 206C, 206M, 206Y and 206K shown in FIG. 21. by transporting theprinting medium 201 at a predetermined speed in the medium transportdirection by the medium transport means (not shown) and performingjetting the nozzles (218C, 218M, 218Y and 218K) of the respectiverecording heads (212C, 212M, 212Y and 212K) in an appropriate timing.

That is, it is possible to form the single dot pattern 202C, the firstcontinuous dot pattern 204C and the second continuous dot pattern 206Cof FIG. 21 by performing jetting from the respective nozzles 218C of thecyan recording head 212C. An inter-dot distance between two dotsoverlapping each other is different in the first continuous dot pattern204C and the second continuous dot pattern 206C. That is, an intervalbetween two times of jetting timings when two dots overlapping eachother are recorded is different in the first continuous dot pattern 204Cand the second continuous dot pattern 206C.

The same is true of the respective colors of M, Y and K, and it ispossible to form the single dot pattern 202M, the first continuous dotpattern 204M and the second continuous dot pattern 206M of FIG. 21 bytransporting the printing medium 201 and performing jetting from therespective nozzles 218M of the magenta recording head 212M of FIG. 22 inan appropriate timing.

It is possible to form the single dot pattern 202Y, the first continuousdot pattern 204Y and the second continuous dot pattern 206Y of FIG. 21by transporting the printing medium 201 and performing jetting from therespective nozzles 218Y of the yellow recording head 212Y of FIG. 22 inan appropriate timing.

Similarly, it is possible to form the single dot pattern 202K, the firstcontinuous dot pattern 204K and the second continuous dot pattern 206Kof FIG. 21 by transporting the printing medium 201 and performingjetting from the respective nozzles 218K of the black recording head212K of FIG. 22 in an appropriate timing.

It is necessary to separate (give a time difference) the jetting timingsof the nozzles adjacent to each other in the horizontal direction inFIG. 22 by a predetermined time such that dots adjacent to each other inthe horizontal direction (main scanning direction) do not overlap inFIG. 21. The “nozzles adjacent to each other in the horizontaldirection” are nozzles adjacent to each other in the projection nozzlearray as the “substantial nozzle array” arranged in the horizontaldirection.

In the configuration shown in FIG. 22, it is possible to form thepattern shown in FIG. 21 by performing jetting in the order of K→Y→M→Caccording to the transport of the printing medium 201 and performingjetting in the order of first row→second row→third row→fourth row amongthe four rows of the two-dimensional nozzle arrangement for therespective colors. However, it is necessary to separate (give a timedifference) the jetting timings of the nozzles of the respective colorsand the respective rows by a predetermined amount such that dotsrecorded by different nozzles do not overlap each other.

The above-described jetting timings are controlled by combining thecharacteristic-parameter-acquisition-chart generation unit 62 (see FIGS.3 and 19) and the printing control device 22 (see FIG. 2) which arealready described above. Instead of the configuration described in FIGS.5 and 6, the configuration described in FIGS. 21 and 22 may be adopted.

<Inclusion of System Characteristic Parameter by Concept of SystemError>

It has been described in the above description that the “system error”within the term “system error absence” or “tolerance to the systemerror” has the meaning of an error changed temporally and/or for eachplace as the change component of the characteristic parameter.

Meanwhile, as already described above, errors having reproducibilitysuch as non-jetting due to nozzle failure and an error in nozzleposition caused by the manufacturing error are included in the systemerror. These errors having reproducibility may be comprehended asparameters indicating the characteristics of the system, and may beconsidered as a parameter of the “system error”. That is, the error ofthe system errors which is capable of being reliably defined by theinput from the user or the measurement based on the reading result of atest chart, that is the error having reproducibility may be consideredas the characteristic parameter of the system. In the presentspecification, the error having reproducibility is referred to as a“characteristic error”. The characteristic error means an error as thesystem characteristic. Since the characteristic error of the systemerrors which is the error having reproducibility is the characteristicparameter of the system, it is possible to generate an optimum halftoneprocessing rule acquired by estimating the characteristic error for thecharacteristic error.

Meanwhile, in the present specification, the error of the system errorswhich is changed temporally and/or for each place, that is, theirregularly changed error is referred to as a “random system error”. Itis possible to design only the halftone to which the tolerance to theerror is applied for the random system error.

It is possible to comprehend that the relationship between thecharacteristic error and the random system error corresponds to therelationship between a representative value such as an expectation value(average value) or a center value related to the distribution of themeasurement values of a certain interest error item and “dispersion”such as a variation from the representative value or a change width.

A further specific example of the system error will be described. As anexample of a common “system error” for the serial scan type ink jetprinting system and the single path type ink jet printing system, thereare each nozzle error of the head, non-jetting and a position shift foreach droplet kind.

The nozzle error includes an error of a liquid droplet in a flyingdirection, an error of a jetting speed, an error of a droplet amount oran error of a dot shape in each nozzle. The jetting speed is representedby the term “drop velocity” in some cases. The error of the dropletamount can be comprehended as the error of the dot density. The dotshape is a synonym for a “dot profile”. Since the error in the flyingdirection, the error of the jetting speed, the error of the dropletamount and the error of the dot shape are errors depending on thedroplet kind in some cases, it is preferable that these errors arecomprehended for each droplet kind.

The nozzle error is the term that comprehensively represents the errorof the nozzle position in the main scanning direction and/or subscanning direction, the error of the dot density, the error of the dotdiameter, the error of the dot shape or an error of an appropriatecombination thereof.

The droplet kind is the kind of liquid droplet corresponding to a dotsize with which the recording can be controlled by the head. Forexample, in the configuration in which the jetting of a small droplet, amedium droplet and a large droplet corresponding to three kinds of dotsizes of a small dot, a medium dot and a large dot can be controlled,the droplet kind is three. The position shift for each droplet kindmeans a landing position error for each droplet kind in the mainscanning direction and/or sub scanning direction.

The nozzle error of each nozzle may determine a value capable of beingtreated as a “characteristic error” which is approximately observed onaverage for each nozzle can be determined, and may be a target of the“random system error” changed temporally and/or for each place.

As an example of the “system error” in the serial scan type ink jetprinting system, there is a bidirectional position shift in scanning, abidirectional position shift for each droplet kind, a head vibrationerror according to the carriage movement or a paper transport error.

The bidirectional position shift is an error in the main scanningdirection of a dot recording position in a case where the jetting isperformed during the movement of the carriage in an outward direction ina reciprocating operation of the carriage and a dot recording positionin the main scanning direction in a case where the jetting is performedduring the movement of the carriage in an inward direction.

The bidirectional position shift for each droplet kind is an error inposition in the main scanning direction and the sub scanning directionfor each droplet kind in a case where the jetting is performed duringthe movement in the outward and inward directions of the carriagemovement.

The head vibration error is caused by the vibration of the driving beltof the carriage, and is observed as a change in dot position in the mainscanning direction and/or the sub scanning direction. The papertransport error is an error in paper sending amount in the sub scanningdirection which is the paper transport direction. The paper transporterror is observed as a recording position error in the sub scanningdirection.

As an example of the “system error” in the single path type ink jetprinting system, there is an error (referred to as a “head modulevibration error”) due to the vibration of the head module constitutingthe line head, or an error (head module attachment error) of anattachment position of each head module. The head module vibration erroris observed as the error in the dot position in the main scanningdirection and/or the sub scanning direction. The head module attachmenterror may also be observed as the error in the dot position in the mainscanning direction and/or the sub scanning direction.

The head module attachment error corresponds to the characteristicerror.

[Chart for Acquiring System Error Parameter]

In FIG. 5, the “characteristic parameter acquisition chart” foracquiring the characteristic parameter has been described. As mentionedabove, since the characteristic parameter can be comprehended as theparameter indicating the characteristic error of the system errors, thecharacteristic parameter can be understood as a kind of system errorparameter. Accordingly, it is understood that the “characteristicparameter acquisition chart” corresponds to one example of a “systemerror parameter acquisition chart”.

As the system error parameter acquisition chart in the single scan typeink jet printing system, the following charts may be used.

Example 1

As the chart for acquiring each nozzle error or non-jetting parameteramong the system errors, the characteristic parameter acquisition chartdescribed in FIG. 5 may be applied.

Example 2

In order to comprehend the nozzle error for each droplet kind such asthe position shift (including the bidirectional position shift) for eachdroplet kind, the characteristic parameter acquisition chart describedin FIG. 5 is generated from the outward path and the inward path. Forexample, in a case where the jetting of three droplet kinds of a smalldroplet, a medium droplet and a large droplet can be controlled, therespective droplet kinds of the small droplet, the medium droplet andthe large droplet, the characteristic parameter acquisition chartdescribed in FIG. 5 may be output and measured for the medium dropletand the large droplet. It is possible to acquire position shiftinformation indicating how much the dot position which is actuallyrecorded is shifted from a target recording position (pixel position)for each droplet kind. The characteristic parameter acquisition chartdescribed in FIG. 5 is generated for the outward path and the inwardpath for each droplet kind. It is possible to acquire the information ofthe position shift related to the carriage movement direction (mainscanning direction) in the outward path and the inward path for eachdroplet kind from the measurement results of the charts.

Example 3

An example of the chart for measuring the head vibration error accordingto the carriage movement is shown in FIG. 23. Here, in order to simplifythe illustration, only the black recording head 112K is schematicallyshown. As shown in FIG. 23, a continuous jetting operation is performedfrom a specific nozzle 118S of the recording head while moving thecarriage, and thus, the head vibration error measurement chart isgenerated. The “continuous jetting operation being performed” mentionedherein means that the jetting is repeated at a cycle of time intervalsenough to record the dots as independent dots which are individuallyseparated (isolated) from each other so as not to overlap each other.

For the sake of convenience in the description, FIG. 23 shows that thedot interval in the main scanning direction or the head vibration errorhighlighted (deformed) so as to be extremely increased. The head isvibrated according to the movement of the carriage, and thus, the shiftamount in the main scanning direction and/or the sub scanning directionis changed.

The output result of the chart shown in FIG. 23 is read by the imagereading device 26 (see FIG. 1) such as the in-line sensor, and the shiftamounts in the main scanning direction and the sub scanning directionfrom an ideal position to be originally jetted are measured for eachdot. How much the actual landing position is shifted from each pixelposition is measured. As the ideal position to be originally jetted, thepixel position is determined to be in a line in the main scanningdirection. The pixel position to be originally jetted in the mainscanning direction is expressed by “n”, and a shift amount Δx(n) in themain scanning direction and a shift amount Δy(n) in the sub scanningdirection with respect to each pixel position n may be measured (seeFIG. 24). “n” indicates a position coordinate (X coordinate) of thepixel on which the jetting is performed in the main scanning direction.n may be an integer from 0 to N. N in this case indicates an integercorresponding to the number of jetted dots. Δx(n) and Δy(n) representthe shifts from the ideal landing position.

FIGS. 25A and 25B show examples of the head vibration error. In FIG.25A, a horizontal axis represents the pixel position n in the mainscanning direction, and a vertical axis represents the position shiftamount in the main scanning direction. In FIG. 25B, a horizontal axisrepresents the pixel position n in the main scanning direction, and avertical axis represents the position shift amount in the sub scanningdirection.

By doing this, the shift amount Δx(n) in the main scanning direction andthe shift amount Δy(n) in the sub scanning direction are calculated asthe function of the pixel position n.

Although the example in which the continuous jetting operation isperformed from the specific single nozzle 118S has been described inFIG. 23, the continuous jetting operation may be performed from aplurality of specific nozzles in a similar manner, the statisticalprocess is performed on the shift amounts Δx(n) and Δy(n) acquired fromthe measurement, and the parameter of the head vibration error may begenerated.

Example 4

The paper transport error is an error indicating a variation in papersending amount. The paper transport error is an error with which the dotposition is shifted due to a paper transport mechanism in the printingsystem. FIG. 26 is an example of a chart for acquiring information ofthe paper transport error. Here, in order to simplify the illustration,only the black recording head 112K is schematically shown. Similarly tothe example of FIG. 23, in a case where the parameter of the papertransport error is acquired, the continuous jetting operation isperformed in the specific nozzle 118S of the recording head, and a lineof a dot array according to the main scanning direction is drawn. Thespecific nozzle 118S of FIG. 23 and the specific nozzle 118S of FIG. 26may be the same nozzle, or may be different nozzles.

As shown in FIG. 26, if a first-row dot array DL1 is drawn, apredetermined amount of paper transport in the sub scanning direction isperformed. The “paper transport” is a synonym for “paper sending” or“sheet sending”. It is assumed that the control amount of thepredetermined of paper transport is Δy₀. A second-row dot array DL2 issimilarly drawn. The predetermined amount Δy₀ of paper transport and thecontinuous jetting operation are repeated, and thus, a plurality of dotarrays DL1, DL2, DL3, . . . is drawn. It is preferable that this chartis recorded by performing scanning only in the outward path of thecarriage movement, or only in the inward path thereof, or in any onethereof.

A pixel position as a jetting command position of each dot in a k-th-rowdot array is represented as (n, k). k is an integer from 1 to m, and mis an integer of 2 or more. A difference y_(av(k+1))−y_(av(k)) betweenan average value y_(av(k)) of sub-scanning-direction positions of therespective dots in the k-th-row dot array and an average valuey_(av(k+1)) of sub-scanning-direction positions of the respective dotsin a (k+1)-th-row dot array is measured as a k-th paper sending amountΔy_(k). An error of the k-th paper transport may be expressed asΔy_(k)−Δy₀.

FIG. 27 shows an example of the distribution of the measurement valuesof Δy_(k) (k=1, 2, . . . , m−1) measured from a paper transport errormeasurement chart. A horizontal axis represents a paper transport errorΔy. The illustrated distribution of the paper sending amount is adistribution according to the normal distribution.

As the system error parameter acquisition chart in the single path typeink jet printing system, the following charts may be used.

Example 5

As the chart for acquiring each nozzle error or non-jetting parameteramong the system errors, the characteristic parameter acquisition chartdescribed in FIG. 21 may be applied.

Example 6

In order to comprehend the nozzle error for each droplet kind such asthe position shift (including the bidirectional position shift) for eachdroplet kind, the characteristic parameter acquisition chart describedin FIG. 21 is generated for each droplet kind. For example, in a casewhere the jetting of three droplet kinds of the small droplet, themedium droplet and the large droplet can be controlled, thecharacteristic parameter acquisition chart described in FIG. 5 may beoutput and may be measured for the small droplet, the medium droplet andthe large droplet. It is possible to acquire position shift informationindicating how much the dot position which is actually recorded isshifted from a target recording position (pixel position) for eachdroplet kind.

Example 7

An example of the chart for the head vibration error parameter in thesingle path type is shown in FIG. 28. For the sake of convenience in thedescription, FIG. 28 shows only the cyan recording head 212C. The cyanrecording head 212C of FIG. 28 is a line head formed by connecting aplurality of head modules 220-j (j=1, 2, . . . , and Nm). Although anexample in which Nm=5 as an example of the number of connected headmodules is illustrated in this drawing, the number of connected headmodules is not particularly limited, and may be arbitrarily designed.

The plurality of head modules 220-j (j=1, 2, . . . , and Nm) is fixed toa common supporting frame 222, and is formed as one head bar as a whole.The dot recording position is changed due to the vibration of the headbar. As shown in FIG. 28, the jetting is continuously performed form thesingle specific nozzle 228S while the printing medium 201 is transportedin the sub scanning direction at a predetermined speed, and the dotarray arranged in the sub scanning direction is recorded. Similarly tothe example described in FIG. 23, the “jetting being continuouslyperformed” means that the jetting is repeated at a cycle of timeintervals enough to record the dots as independent dots which areindividually separated (isolated) from each other so as not to overlapeach other.

Similarly to FIG. 23, for the sake of convenience in the description,FIG. 28 shows that the dot interval in the sub scanning direction or thehead vibration error highlighted (deformed) so as to be extremelyincreased. The shift amount in the main scanning direction and/or thesub scanning direction is changed due to the vibration of the head bar.

The output result of the chart shown in FIG. 28 is read by the imagereading device 26 (see FIG. 1) such as the in-line sensor, and the shiftamounts in the main scanning direction and the sub scanning directionfrom an ideal position to be originally jetted are measured for eachdot. How much the actual landing position is shifted from each pixelposition is measured. As the ideal position to be originally jetted, thepixel position is determined to be in a line in the sub scanningdirection. The pixel position to be originally jetted in the subscanning direction is expressed by “n”, and a shift amount Δx(n) in themain scanning direction and a shift amount Δy(n) in the sub scanningdirection with respect to each pixel position n may be measured. Here,“n” indicates a position coordinate (Y coordinate) of the pixel on whichthe jetting is performed in the sub scanning direction.

Similarly to the example described in FIG. 23, it is possible to acquirethe head vibration error parameter in the single path type from themeasurement result of the chart of FIG. 28.

Example 8

As the system error specific to the single path type, there is the headmodule attachment error. FIG. 29 is an example of the chart foracquiring the head module attachment error parameter. The respectivehead modules 220-j (j=1, 2, . . . , and Nm) are attached so as to beshifted from attachment positions (ideal attachment positions) in thedesign. The attachment positions of the respective head modules 220-j(j=1, 2, . . . , and Nm) may include a main scanning direction error, asub scanning direction error and an in-surface rotation direction error.The dot recording position is shifted from the ideal position due to thehead module attachment error.

In the chart shown in FIG. 29, in the respective nozzle groups of thehead modules 220-j (j=1, 2, . . . , and Nm), the jetting is performed ona pixel array arranged in a line in the main scanning direction, and adot array D_(s)(j) for each of the head modules 220-j (j=1, 2, . . . ,and Nm) is recorded.

A central position of gravity G(j) of a group of dot arrays D_(s)(j) andan angle of inclination θ(j) with respect to the main scanning directionare calculated from the density distributions thereof for the dot arrayD_(s)(j) for each of the head modules 220-j (j=1, 2, . . . , and Nm)from the read image of the chart (see FIGS. 30A and 30B).

A central position of gravity G₀(j) is determined for each originallyintended (that is, ideally designed) dot array D_(s)(j). Accordingly, asshown in FIG. 30(A), it is possible to comprehend the shift of thecentral position of gravity indicating how much the central positionG₀(j) of gravity of the dot array D_(s)(j) calculated by reading thechart in both directions of the main scanning direction and the subscanning direction is shifted from the ideal central position Go(j) ofgravity. It is possible to comprehend the main scanning direction errorand the sub scanning direction error from the shift of the centralposition of gravity. Since it is assumed that the head modules 220-j(j=1, 2, . . . , and Nm) are attached while being rotated in thesurface, the angle of inclination θ(j) of the dot array D_(s)(j) withrespect to the main scanning direction is also measured as shown in FIG.30B. The angle of inclination θ(j) indicates the in-surface rotationdirection error.

[Accumulation and Utilization of System Error Parameter]

The “head module attachment error” described above is not temporallychanged, and corresponds to the characteristic error which is reliablydetermined due to the attachment of the head module. Meanwhile, therespective error items such as each nozzle error (including each nozzleerror for each droplet kind), bidirectional position shift (includingthe bidirectional position shift for each droplet kind), the headvibration error and the paper transport error may be temporally changed.

Accordingly, it is preferable that the tolerance design to the systemerror is performed by accumulating the acquiring results of the systemerror parameters acquired from the respective charts in a storage unitother than the memory, updating the distribution data of the systemerrors including accumulation data of the system error parametersacquired in the past and the newly acquired system error parameters anddetermining the “random system error” based on the latest updated systemerror distribution.

As for the characteristic errors included in the system errors, it ispreferable that the value of the “characteristic error” is updated fromthe data distribution including the accumulation data of the systemerror parameters acquired in the past and the newly acquired systemerror parameters.

[Simulation Image Generation and Image Quality Evaluation in DesigningTolerance to System Error]

A total evaluation value (weighted sum) for each level is used as animage quality evaluation value by performing the simulation imagegeneration and image quality evaluation in a case where the systemerrors are classified in terms of the characteristic error and therandom system error and in a case where the tolerance design to thesystem error is performed when the halftone processing rule is generatedfor each level of the plurality of random system errors. A totalevaluation value (weighted sum) for each level is used as an imagequality evaluation value by performing the simulation image generationand the image quality evaluation in a case where the tolerance design tothe system error is performed when the halftone processing rule isgenerated for each level of the plurality of random system errors.

The “plurality of levels” of the random system error added when thesimulation image is generated follows the system error distribution ofthe printing system.

FIG. 31 is a graph showing the relationship between the system errordistribution and the level of the random system error reflected on thegeneration of the simulation image.

A horizontal axis of FIG. 31 represents the system error. A specificitem of the system error may be each nozzle error, the bidirectionalposition shift, the head vibration error, or the paper transport error.

As shown in FIG. 31, the system errors are distributed so as to beshifted in a plus direction and a minus direction with the value A ofthe characteristic error as its center. The plurality of levels of therandom system error is determined within a spreading range of the systemerror distribution. In the example of FIG. 31, an example in which fourlevels of ±σ and ±2σ are determined using the standard deviation σ ofthe system error distribution is illustrated. The value A of thecharacteristic error corresponds to an average value in the system errordistribution. The present embodiment is not limited to the configurationin which the levels are defined using the standard deviation σ, and thelevels may be determined using an arbitrary value.

In a case where the four levels of “−2σ”, “−σ”, “+σ” and “+2σ” aredetermined as the error amount added as the random system error when thesimulation image is generated, the simulation image for each level isgenerated by adding the errors of the respective levels, and the imagequality is evaluated for the simulation image.

The image quality evaluation value as the total value is calculated byperforming the evaluation on the simulation image for each level. Inthis case, the frequency of giving each random system error having theplurality of levels may follow the distribution shown in FIG. 31. The“frequency” following the system error distribution means that moresimulation images are generated near the center value of thedistribution and the evaluation values of the simulation images arecalculated.

Alternatively, a weighted sum may be calculated by multiplying weightingfactors following the distribution shown in FIG. 31 to the simulationimages of the random system errors of the respective levels or theevaluation values.

For example, a case where four levels of “+a1”, “+a2”, “−a1” and “−a2”are determined as the plurality of levels of the random system errorfrom the system error distribution will be described as shown in FIG.32. However, the a1 and a2 are values that satisfy “0<a1<a2”. In orderto simplify the description, in a case where it is assumed that thecenter value (average value) of the system error distribution is “0” anda distribution function f(x) is the normal distribution, the levels aresymmetrically set with respect to the plus and minus directions.

In this case, if the evaluation values of the respective simulationimages to which the random system error of each level is added arerespectively represented as Val[+a1], Val[+a2], Val[−a1] and Val[−a2],the image quality evaluation value Total_Value as the total evaluationvalue which is the total evaluation value of the simulation image towhich the system error of each level is added is expressed by thefollowing expression.Total_Value=A1×Val[+a1]+A2×Val[+a2]+A3×Val[−a1]+A4×Val[−a2]   Expression(5)

The weighting factors A1, A2, A3 and A4 follow the system errordistribution of FIG. 32. That is, if the distribution function of thesystem error distribution is expressed by f(x), f(−a1)=f(a1) andf(−a2)=f(a2), and A1=A3=u×f(a1) and A2=A4=u×f(a2) by using a positiveproportionality constant u.

In order to simplify the description, although it has been described inFIG. 32 that the four levels are symmetrically set in the plus and minusdirections in a case where the center value (average value) of thesystem error distribution is “0” and the distribution function f(x) isthe normal distribution, the distribution function may be determinedbased on the actual chart measurement value, and it is possible toarbitrarily set the plurality of levels within the spreading range ofthe distribution.

[Application to Expression for Calculating Image Quality EvaluationValue]

If the expressions (1) to (4) for image quality evaluation alreadydescribed above are corrected in terms of the characteristic error andthe random system error as the change component, the followingexpressions are acquired. That is, the description of granularityevaluation value [system error absence] described in Expressions (1) to(4) may be comprehended to be replaced with granularity evaluation value[system error presence (characteristic error presence)], and thedescription of granularity evaluation value [system error presence] maybe comprehended as granularity evaluation value [random system errorpresence]. The description of streak evaluation value [system errorpresence] may be comprehended as streak evaluation value [random systemerror presence]. Hereinafter, the correction expressions corrected byintroducing the viewpoint described in Expression (5) and FIG. 32 toeach of Expressions (1) to (4) will be described.

[1] Dither Method

The following Expression (6) may be used as the correction expression ofExpression (1).Image quality evaluation value=granularity evaluation value [randomsystem error absence (characteristic error presence)]+α×{A1×(granularityevaluation value [system error presence(+a1)]+granularity evaluationvalue [system error presence(−a1)])+A2×(granularity evaluation value[system error presence(+a2)]+granularity evaluation value [system errorpresence(−a2)])+ . . . }+β×{A1×(streak evaluation value [system errorpresence(+a1)]+streak evaluation value [system errorpresence(−a1)])+A2×(streak evaluation value [system errorpresence(+a2)]+streak evaluation value [system error presence(−a2)])+ .. . }   Expression (6)

a1, a2, A1 and A2 follow the relationship described in FIG. 32. Theevaluation may be performed using Expression (6) instead of Expression(1).

[2] Error Diffusion Method

Similarly to the dither method, as for the error diffusion method, thefollowing Expression (7) may be used as the correction expression ofExpression (2) in the already described error diffusion method.

Granularity Evaluation Value [System Error Presence]=α×{A1×{granularity evaluation value [system error presence (addition of“+a1” error to first group)]+granularity evaluation value [system errorpresence (addition of “+a1” error to second group)]+ . . . +granularityevaluation value [system error presence (addition of “−a1” error tofirst group)]+granularity evaluation value [system error presence(addition of “−a1” error to second group)]+ . . . }+A2×{granularity evaluation value [system error presence (addition of“+a2” error to first group)]+granularity evaluation value [system errorpresence (addition of “+a2” error to second group)]+ . . .+granularity evaluation value [system error presence (addition of “−a2”error to first group)]+granularity evaluation value [system errorpresence (addition of “−a2” error to second group)]+ . . . }+ . . . }+β×{A1×{streak evaluation value [system error presence (addition of“+a1” error to first group)]+streak evaluation value [system errorpresence (addition of “+a1” error to second group)]+ . . .+streak evaluation group [system error presence (addition of “−a1” errorto first group)]+streak evaluation value [streak error presence(addition of “−a1” error to second group)]+ . . . }+A2×{streak evaluation value [system error presence (addition of “+a2”error to first group)]+streak evaluation value [system error presence(addition of “+a2” error to second group)]+ . . .+streak evaluation value [system error presence (addition of “−a2” errorto first group)]+streak evaluation value [system error presence(addition of “−a2” error to second group)]+ . . . }+ . . . }  Expression(7)

The evaluation may be performed using Expression (7) instead ofExpression (2).

[3] Case where Void-and-Cluster Method is Used for Dither Method

The following Expression (8) may be used as the correction expression ofExpression (3) in the void-and-cluster method.Image quality evaluation value=energy [random error absence(characteristic error presence)]+α×{A1×(energy [system errorpresence(+a1)]+energy [system error presence (−a1)])+A2×(energy [systemerror presence(+a2)]+energy [system error presence(−a2)])+. . .}+β×{A1×(streak energy [system error presence(+a1)]+streak energy[system error presence(−a1)])+A2×(streak energy [system errorpresence(+a2)+streak energy [system error presence(−a2)])+ . . .}  Expression (8)

The evaluation may be performed using Expression (8) instead ofExpression (3).

[4] DBS Method

In the DBS method, the same evaluation method as the example describedin Expressions (6) to (8) described above when the simulation image maybe evaluated.

[5] Evaluation Expression in Automatic Selection of Halftone Process

The following Expression (9) may be used as the correction expression ofExpression (4) described using the image quality evaluation in a casewhere the system automatically selects one halftone processing rule fromthe two or more kinds of halftone processing rules.Image quality evaluation value=p×granularity evaluation value [randomsystem error absence (characteristic error presence)]+q×{A1×{granularityevaluation value [system error presence (addition of “+a1” error tofirst group)]+granularity evaluation value [system error presence(addition of “+a1” error to second group)]+ . . . +granularityevaluation value [system error presence (addition of “−a1” error tofirst group)]+granularity evaluation value [system error presence(addition of “−a1” error to second group)]+ . . . }+A2×{granularity evaluation value [system error presence (addition of“+a2” error to first group)]+granularity evaluation value [system errorpresence (addition of “+a2” error to second group)]+ . . . +granularityevaluation value [system error presence (addition of “−a2” error tofirst group)]+granularity evaluation value [system error presence(addition of “−a2” to second group)]+ . . . } . . . }+r×{A1×{streakevaluation value [system error presence (addition of “+a1” error tofirst group)]+streak evaluation value [system error presence (additionof “+a1” error to second group)]+ . . . +streak evaluation value [systemerror presence (addition of “−a1” error to first group)]+streakevaluation value [system error presence (addition of “−a1” error tosecond group)]+ . . . }+A2×{streak evaluation value [system error presence (addition of “+a2”error to first group)]+streak evaluation value [system error presence(addition of “+a2” error to second group)]+ . . . +streak evaluationvalue [system error presence (addition of “−a2” error to firstgroup)]+streak evaluation value [system error presence (addition of“−a2” error to second group)]+ . . . }+ . . . }  Expression (9)

Here, in order to simplify the description, the case where it is assumedthat a one-dimensional distribution is used as the system errordistribution as in FIG. 31 or 32 and it is assumed that the calculationexpression of the image quality evaluation value is also theone-dimensional error has been described. However, each nozzle error orthe head vibration error actually represents a two-dimensional errordistribution in the main scanning direction and the sub scanningdirection as shown in FIGS. 33 to 35.

FIG. 33 is a diagram showing that the two-dimensional error distributionin the main scanning direction and the sub scanning direction isrepresented as shades. FIG. 34 is a sectional view of the errordistribution along the main scanning direction in the two-dimensionalerror distribution shown in FIG. 33. FIG. 35 is a sectional view of theerror distribution along the sub scanning direction in thetwo-dimensional error distribution shown in FIG. 33.

For example, as shown in FIGS. 34 and 35, in a case where four levels“+a1”, “+a2”, “−a1” and “−a2” are determined in the main scanningdirection, four levels “+b1”, “+b2”, “−b1” and “−b2” are determined inthe sub scanning direction as the plurality of levels of the randomsystem error from the system error distribution, the image qualityevaluation value Total_Value as an example is expressed by the followingExpression (10) instead of Expression (5).Total_Value=A1×Val[+a1,0]+A2×Val[+a2,0]+A3×Val[−a1,0]+A4×Val[−a2,0]+B1×Val[0,+b1]+B2×Val[0,+b2]+B3×Val[0,−b1]+B4Val[0,−b2]+C1×Val[+a1,+b1]+C2×Val[+a1,−b1]+C3×Val[−a1,+b1]+C4×Val[−a1,−b1]+D1×Val[+a2,+b2]+D2×Val[+a2,−b2]+D3×Val[−a2,+b2]+D4×Val[−a2,−b2]  Expression(10)

Here, the evaluation value of the simulation image to which the randomsystem error having the error amounts of x in the main scanningdirection and y in the sub scanning direction is added are expressed asVal[x,y]. The weighting factors A1 to A4, B1 to B4, C1 to C4 and D1 toD4 follow the system error distribution shown in FIGS. 33 to 35. Thatis, if the distribution function of the system error distribution isexpressed as f(x,y), A1=A3=u×f(a1,0), A2=A4=u×f(a2,0), B1=B3=u×f(0,b1),B2=B4=u×f(0,b2), C1=C2=C3=C4=u×f(a1,b1), and D1=D2=D3=D4=u×f(a2,b2).Here, u indicates a positive proportionality constant.

In the generation of the described simulation image and the imagequality evaluation expressed as Expressions (1) to (10), the method ofgenerating the simulation image having the system error and evaluatingthe image quality corresponds to the embodiment in which the simulationimage is generated by independently adding the predetermined systemerror to each pixel group of the halftone image, which belongs to theprinting order, the path and timing, and the evaluation value iscalculated. However, the simulation image acquired by adding thepredetermined system error to all the pixel groups belonging to theprinting order, the path and the timing may be generated, and the imagequality may be evaluated. The simulation image may be generated byindependently adding the system errors of the respective items of eachnozzle error (including the position shift for each droplet kind), thenon-jetting, the bidirectional position shift (including thebidirectional position shift for each droplet kind), the head vibrationerror and the paper transport error to the halftone image, and the imagequality may be evaluated. Alternatively, the simulation image may begenerated by simultaneously adding the system errors of all the items tothe halftone image, and the image quality may be evaluated.

In addition, the method of generating the simulation image having thesystem error (including the setting of the error level) and evaluatingthe image quality may be realized as various embodiments withoutdeparting the gist of the present invention.

[Configuration of Image Processing Device According to Third Embodiment]

FIG. 36 is a block diagram of major parts for describing the function ofan image processing device according to a third embodiment. In FIG. 36,the same or similar elements as or to those of the configurationdescribed in FIG. 3 will be assigned to the same reference numerals, andthe description thereof will be omitted.

The image processing device 20 according to the third embodiment shownin FIG. 36 includes a system-error-parameter acquisition unit 53, asystem-error-parameter storage unit 55, and a system error setting unit67. The system-error-parameter acquisition unit 53 is means foracquiring parameters related to the system errors. Thesystem-error-parameter acquisition unit 53 corresponds to one example of“parameter acquisition means”. The system-error-parameter acquisitionunit 53 has the same function as that of the characteristic parameteracquisition unit 52 described in FIG. 3, and has a function of thecharacteristic parameter acquisition unit 52.

The system-error-parameter storage unit 55 is means for storing systemerror parameters acquired from the system-error-parameter acquisitionunit 53. The system-error-parameter storage unit 55 includes acharacteristic error storage unit 55A, and a random-system-error storageunit 55B. The characteristic error storage unit 55A is a storage unitthat stores characteristic error parameters of the system errors. Therandom-system-error storage unit 55B is a storage unit that storesrandom-system-error parameters of the system errors. Thesystem-error-parameter storage unit 55 accumulates data of parameteracquired in the past. The control unit 50 performs the calculation of astatistical process from the distribution of a data group of the systemerrors stored in the system-error-parameter storage unit 55, anddetermines a value of the characteristic error corresponding to thecenter value of the system error distribution and a plurality of levelsof the random system errors.

The system-error-parameter storage unit 55 has a function of thecharacteristic parameter storage unit 54 described in FIG. 3. Thesystem-error-parameter storage unit 55 corresponds to one example ofstorage means.

The system error setting unit 67 is means for setting the parametersrelated to the system errors assumed in a case where the printing isperformed by the printing system 10 (see FIG. 1). The system errorsetting unit 67 sets a parameter as a simulation condition forgenerating a simulation image by the simulation image generation unit68. The system error setting unit 67 corresponds to one example of“setting means”. The process of causing the system error setting unit 67to set the system error corresponds to one example of a “system errorsetting step”. The control unit 50 may have the function of the systemerror setting unit 67.

The simulation image generation unit 68 reflects the system errorindicated by the parameter set by the system error setting unit 67 onthe halftone processing result, and generates a high-resolutionsimulation image by the halftone processing result. The simulation imagegeneration unit generates the high-resolution simulation image once,performs smoothing on the generated simulation image, and generates thesimulation image by converting the smoothed simulation image into alow-resolution simulation image. The step of causing the simulationimage generation unit 68 to generate the simulation image corresponds toone example of a “simulation image generation step”. The evaluationvalue calculation unit 70 calculates an evaluation value for evaluatingthe image quality of the simulation image generated by the simulationimage generation unit 68. The evaluation value calculation unit 70functions as calculation means for calculating the summation of theevaluation values of the simulation image for the respective levels or aweighted sum by multiplying the weighting factors to the evaluationvalues of the simulation image for the respective levels.

The image processing device 20 allows the user to directly input thecharacteristic parameters related to the characteristics of the printingsystem 10 by using the input device 34. That is, the aspect of thecharacteristic parameter acquisition unit 52 of the image processingdevice 20 may be a configuration in which the user directly inputs thecharacteristic parameters related to the characteristics of the printingsystem 10 by using the input device 34, may be a configuration in whichthe characteristic parameters are automatically acquired from themeasurement result of the characteristic parameter acquisition chart(system error parameter acquisition chart), or may be a combination ofthese configurations. The input device 34 corresponds to one example of“information input means”. The image processing devices 20 described inthe FIGS. 3 and 19 may have the configuration in which the parameterscan be directly input from the input device 34.

The image processing device 20 shown in FIG. 36 has the configuration inwhich the generation and evaluation of the simulation image described inExpressions (6) to (9) can be performed.

The processing contents performed by the image processing devices 20according to the respective embodiments described above can becomprehended as an image processing method.

[Description of Updating of Characteristic Parameter According to FourthEmbodiment]

Hereinafter, the updating of the characteristic parameter according to afourth embodiment will be described.

<Entire Configuration>

FIG. 37 is a block diagram showing the configuration of a printingsystem according to a fourth embodiment. In FIG. 37, the sameconfigurations as those of FIG. 3 will be assigned to the same referencenumerals, and the description thereof will be appropriately omitted.

The updating of the characteristic parameter according to the fourthembodiment, to be described below, means that the characteristicparameter is updated in a case where a difference between an existingcharacteristic parameter which is a characteristic parameter acquired inthe past and a new characteristic parameter newly acquired exceeds aspecified value previously acquired.

That is, an image processing device 20A shown in FIG. 37 has aconfiguration in which a characteristic parameter update determinationunit 230 and a specified value acquisition unit 232 are added to theimage processing device 20 shown in FIG. 3.

The characteristic parameter update determination unit 230 functions ascharacteristic parameter update determination means for determiningwhether or not to update the characteristic parameter. The determinationof whether or not to update the characteristic parameter is performedbased on the specified value acquired by the specified value acquisitionunit 232.

The specified value acquisition unit 232 functions as specified valueacquisition means for acquiring the specified value used to determinewhether or not to update the characteristic parameter of thecharacteristic parameter update determination unit 230.

As an example of the aspect in which the specified value is acquired,there are an aspect in which the specified value is calculated by aspecified value calculation unit (not shown) functioning as specifiedvalue calculation means, an aspect in which a specified value tablewhich is a specified value table (not shown) functioning as specifiedvalue storage means and stores the specified values which are acquiredand accumulated in the past is referred to, and an aspect in which thespecified value input (designated) using the input device 34 isacquired.

As the existing characteristic parameter, the characteristic parameterstored in the characteristic parameter storage unit 54 shown in FIG. 37may be applied. As the existing characteristic parameter, the latestacquired characteristic parameter of the characteristic parametersacquired in the past may be applied, or a representative value of thecharacteristic parameters acquired in the past such as an average valueof the characteristic parameters acquired in the past may be used.

As the difference between the existing characteristic parameter and thenew characteristic parameter, a difference between the existingcharacteristic parameter and the new characteristic parameter, which iscalculated by subtracting the existing characteristic parameter from thenew characteristic parameter, or an absolute value of the differencebetween the existing characteristic parameter and the new characteristicparameter may be used.

As the difference between the existing characteristic parameter and thenew characteristic parameter, a ratio of the new characteristicparameter to the existing characteristic parameter, which is calculatedby dividing the new characteristic parameter by the existingcharacteristic parameter may be used.

The specified value may be constant (fixed value), or may be changedwhenever the characteristic parameter is acquired. That is, thespecified value acquisition unit 232 may acquire the fixed value as thespecified value once, or may acquire the specified value multiple times.

In the aspect in which the specified value is updated, it is preferablethat the past specified value (the history of the specified value) isretained (stored). In a case where the history of the specified value isnot retained, the specified value may be retained within the printingsystem, or the user may designate (input) the specified value. In anaspect in which the user designates the specified value, a specifiedvalue designation unit (specified value input unit) is provided in theprinting system. The input device 34 may be used as the specified valuedesignation unit (specified value input unit).

<Description of Method of Generating Halftone Processing Rule to whichUpdating of Characteristic Parameter According to Fourth Embodiment isApplied>

FIG. 38 is a flowchart of a method of generating the halftone processingrule to which the updating of the characteristic parameter according tothe fourth embodiment is applied. Acharacteristic-parameter-acquisition-chart output step S100, an imagereading step S101 and a characteristic parameter acquisition step S102shown in FIG. 38 are the same as thecharacteristic-parameter-acquisition-chart output step S10, the imagereading step S11 and the characteristic parameter acquisition step S12,and thus, the description thereof will be omitted.

The specified value acquisition step S103 shown in FIG. 38 acquires thespecified value. The specified value acquisition step S103 is performedby the specified value acquisition unit 232 shown in FIG. 37. As anaspect of the specified value acquisition step, there are a specifiedvalue calculation step of calculating the specified value, aspecified-value-table referring step of referring to the table thatstores the specified value, or a specified value acquisition step ofacquiring the specified value input through the specified value inputstep of acquiring the input specified value.

If the specified value through the specified value acquisition step S103shown in FIG. 38 is acquired, the step proceeds to a characteristicparameter update determination step S104.

In the characteristic parameter update determination step S104, it isdetermined whether or not to update the characteristic parameterdepending on whether or not the difference between the existingcharacteristic parameter and the new characteristic parameter acquiredthrough the characteristic parameter acquisition step S102 exceeds thespecified value.

In a case where it is determined as No in the characteristic parameterupdate determination step S104, that is, the difference between theexisting characteristic parameter and the new characteristic parameteracquired through the characteristic parameter acquisition step S102 isequal to or less than the specified value, the step proceeds to anending step.

Meanwhile, in a case where it is determined as Yes in the characteristicparameter update determination step S104, that is, the differencebetween the existing characteristic parameter and the new characteristicparameter exceeds the specified value, the step proceeds to acharacteristic parameter updating step S105.

In the characteristic parameter updating step S105, the characteristicparameter applied to the generation of the halftone processing rule isupdated. That is, the existing characteristic parameter is updated tothe new characteristic parameter, and the step proceeds to ahalftone-processing-rule generation step S106.

In the halftone-processing-rule generation step S106, the two or morekinds of halftone processing rules of which the priorities of therequirements for the halftone process are different are generated byusing the characteristic parameter updated through the characteristicparameter updating step S105.

A halftone-selection-chart output step S107 and a halftone selectionoperating step S108 have the same contents as those of thehalftone-selection-chart output step S16 and the halftone selectionoperating step S18 shown in FIG. 4, and thus, the description thereofwill be omitted.

The updating of the characteristic parameter may be performed when anarbitrary printing job is started, may be performed during the executionof an arbitrary printing job (for example, at a regular interval such asonce every 100 pages or once every 1000 pages), or may be performed whenthe user inputs (for example, the user brings the image quality intoquestion). The updating of the characteristic parameter may be performedwhen the printing system (device) is started.

<Description of Updating of Characteristic Parameter in a Case whereSystem Error is Applied to Specified Value>

FIG. 39 is an explanatory diagram of an example of the updating of thecharacteristic parameter in a case where the system error is applied tothe specified value. The image processing device 20A shown in FIG. 37may determine the specified value based on the random characteristicerror. That is, the specified value acquisition unit 232 shown in FIG.37 and the specified value acquisition step S103 shown in FIG. 38 mayacquire the specified value determined based on the random system errorwhich is the irregularly changed error as the characteristics of theprinting system.

±σ and ±2σ shown in FIG. 39 are examples of the specified valuesdetermined based on the random system error with characteristic error Aits center. σ indicates a standard deviation of the random systemerrors, and it is possible to determine whether or not to update thecharacteristic parameter by determining ±σ, ±2σ or σ×σ as the specifiedvalue. α is an arbitrary positive real number excluding 0. For example,in a case where the specified value is ±2σ, if the difference betweenthe existing characteristic parameter and the new characteristicparameter is B shown in FIG. 39, since the difference B between theexisting characteristic parameter and the new characteristic parameterexceeds the specified 2σ, the characteristic parameter is updated.

In a case where the random system error is changed by performing theacquiring (updating) of the characteristic parameter multiple times, itis preferable that the specified value is updated depending on thechange of the random system error.

The updating of the characteristic parameter may be performed byupdating the existing characteristic parameter to the new characteristicparameter, or may be performed by updating the existing characteristicparameter to the average value of the existing characteristic parameterand the new characteristic parameter. The characteristic parameter maybe updated to the latest existing characteristic parameter of theexisting characteristic parameters or as much of the existingcharacteristic parameters as the previously determined number from thenewest parameter and the value calculated using the new characteristicparameter. In this case, it is not necessary to store all thecharacteristic parameters acquired in the past, and the latest existingcharacteristic parameter or as much of the existing characteristicparameters as the previously determined number from the newestparameters may be stored, and it is possible to reduce the storagecapacity of the characteristic parameter storage unit 54 (see FIG. 3)that stores the existing characteristic parameters.

Even in a case where the difference between the existing characteristicparameter and the new characteristic parameter is equal to or less thanthe specified value, that is, even in the characteristic parameter isnot updated, the random system error may be changed based on the newcharacteristic parameter. The specified value may be changed accordingto the change of the random system error.

It is possible to use the characteristic error (shown by referencenumeral A in FIG. 39) as the characteristic parameter. That is, in acase where the difference between the characteristic error of theexisting characteristic parameter and the error characteristics of thenew characteristic parameter exceeds the specified value (for example,±σ or ±2σ described in FIG. 39), it is possible to update thecharacteristic parameter.

<Specific Example of Characteristic Parameter to be Updated>

Hereinafter, a specific example of a characteristic parameter to beupdated will be described. The description of the already describedcharacteristic parameters among the characteristic parameters to beillustrated below will be appropriately omitted.

As the characteristic parameters to be updated, there are the averagedot density of the plurality of printing elements, the average dotdiameter in the plurality of printing elements, the average dot shape inthe plurality of printing elements and the landing interference in theplurality of printing elements, which are the characteristic parameterscommon to the plurality of printing elements.

The specified value in a case where the characteristic parameters to beupdated are the average dot density in the plurality of printingelements, the average dot diameter in the plurality of printing elementsand the average dot shape in the plurality of printing elements may bean absolute value, or may be a ratio between the existing average dotdensity in the plurality of printing elements, the existing average dotdiameter in the plurality of printing elements and the existing averagedot shape in the plurality of printing elements.

In a case where the tolerance design is performed while the average dotdensity, the average dot diameter and the average dot shape in theplurality of printing elements are regarded as the characteristic errorsand a variation in dot density, a variation in dot diameter and avariation in dot shape in the individual printing element with respectto the average dot density, the average dot diameter and the average dotshape in the plurality of printing elements are regarded as the randomsystem errors, the characteristic errors or the random system errors areupdated or the characteristic errors and the random system errors areupdated according to the following order.

Initially, the new characteristic errors (the average dot density, theaverage dot diameter, the average dot shape in the plurality of printingelements) and the new random system errors (a variation in dot density,a variation in dot diameter and a variation in dot shape in theindividual printing element) are acquired from the new characteristicparameters. Subsequently, the difference between the existingcharacteristic error and the new characteristic error is calculated, andit is determined whether or not the difference between the existingcharacteristic error and the new characteristic error exceeds thespecified value. In a case where the difference between the existingcharacteristic error and the new characteristic error exceeds thespecified value, the characteristic error is updated.

The difference between the existing random system error and the newrandom system error is calculated, it is determined whether or not thedifference between the existing random system error and the new randomsystem error exceeds the specified value, and in a case where thedifference between the existing random system error and the new randomsystem error exceeds the specified value, the random system error isupdated.

As the specified value in a case where the characteristic parameter tobe updated is the landing interference, an index indicating thedifference such as the summation of the absolute values of New(x)−Old(x)which are the differences between Old(x) which are the existing changeamounts of the inter-dot distance and New(x) which are the new changeamounts of the inter-dot distance in the relationship between theinter-dot distance and the change amount of the inter-dot distance shownin FIG. 40, the summation of squares thereof, the summation ofNew(x)/Old(x) which are ratios between the existing change amounts ofthe inter-dot distance and the new change amounts of the inter-dotdistance, or the summation of squares thereof, or an index indicatingsimilarity such as a correlation coefficient may be applied.

The summation of the absolute values of the differences between theexisting change amounts of the inter-dot distance and the new changeamounts of the inter-dot distance is expressed by Σ|New(x)−Old(x)|. Thesummation of squares of the distances between the existing changeamounts of the inter-dot distance and the new change amounts of thedot-inter distance is expressed by Σ(New(x)−Old(x))². The summation ofthe ratios between the existing change amounts of the inter-dot distanceand the new change amounts of the inter-dot distance is expressed byΣ(New(x)/Old(x)). The summation of squares of ratios between theexisting change amounts of the inter-dot distance and the new changeamounts of the inter-dot distance is expressed by Σ(New(x)/Old(x))².AveNew represents the average of the new change amount of the inter-dotdistance, AveOld represents the average of the existing change amount ofthe inter-dot distance, and the correlation coefficient is expressed byΣ{(New(x)−AveNew)×(Old(x)−AveOld)}/{Σ(New(x)−AveNew)²×Σ(Old(x)−AveOld)²}.

The relationship between an inter-dot recording time difference and thechange amount of the inter-dot distance is schematically represented inthe drawing in which a horizontal axis in FIG. 40 represents theinter-dot recording time difference instead of the inter-dot distance.The inter-dot recording time difference is a landing time differencebetween arbitrary two dots or a jetting time difference betweenarbitrary two dots. As the specified value in a case where thecharacteristic parameter is the landing interference, an index such asthe summation of the absolute values of the differences between theexisting change amounts of the inter-dot distance and the new changeamounts of the inter-dot distance in the relationship between theinter-dot recording time difference and the change amount of theinter-dot distance, the summation of squares of the differences betweenthe existing change amounts of the inter-dot distance and the new changeamounts of the inter-dot distance, the summation of the ratios betweenthe existing change amounts of the inter-dot distance and the new changeamounts of the inter-dot distance, or the summation of squares of ratiosbetween the existing change amounts of the inter-dot distance and thenew change amounts of the inter-dot distance, or an index indicatingsimilarity such as a correlation coefficient may be applied.

As another example of the characteristic parameter to be updated, thereare the dot density for each printing element, the dot diameter for eachprinting element, the dot shape for each printing element, the dotforming position shift for each printing element, the non-jetting foreach printing element and the dot position shift for each droplet kindfor each printing element which are the characteristics of theindividual printing element. The dot forming position shift for eachprinting element corresponds to a dot recording position error for eachprinting element. The non-jetting for each printing element correspondsto recording inexecutable abnormality for each printing element.

The specified value in a case where the dot density for each printingelement, the dot diameter for each printing element and the dot shapefor each printing element are the characteristic parameters may be theabsolute value, or may be the ratio between the existing dot density foreach printing element, the existing dot diameter for each printingelement and the existing dot shape for each printing element. Onespecified value may be determined using an arbitrary printing elementgroup such as the printing element array and the plurality of printingelement arranged adjacent to each other as its target.

As the specified value in a case where the non-jetting for each printingelement is the characteristic parameter, the characteristic parametermay be immediately updated in a case where the non-jetting occurs in theprinting element, or the characteristic parameter may be updated in acase where there are as much of the printing elements of the printingelement group (the plurality of printing elements arranged so as to beadjacent to each other) such as the printing element array as thepreviously determined number. For example, there is an aspect in whichthe characteristic parameter is updated in a case where the non-jettingoccurs in 10% of printing elements using the one-row printing elementarray as its target.

In a case where the dot position shift for droplet kind for printingelement is the characteristic parameter, since the characteristics ofthe dot position shift may be different for each droplet kind even inthe same printing element, the specified value may be determined foreach droplet kind.

As another example of the characteristic parameter to be updated, thereare a paper transport error difference, a head vibration error accordingto the carriage movement, a printing position shift in scanning for eachdroplet kind, a bidirectional printing position shift in scanning, andwhich are the characteristic parameters specific to the serial scantype. The bidirectional printing position shift in scanning correspondsto a bidirectional printing position shift. The bidirectional printingposition shift in scanning for each droplet kind corresponds to abidirectional printing position shift for each droplet kind. The headvibration error according to the carriage movement corresponds to avibration error of the image forming unit. The paper transport errorcorresponds to a transport error of the printing medium.

As the specified value in a case where the head vibration erroraccording to the carriage movement is the characteristic parameter, anindex indicating a difference between an existing head vibration erroraccording to the carriage movement and a new head vibration erroraccording to the carriage movement may be applied. As the indexindicating the difference between the existing head vibration erroraccording to the carriage movement and the new head vibration erroraccording to the carriage movement, the summation of the absolute valuesof the differences between the existing position shift amounts in themain scanning direction and the new position shift amounts in the mainscanning direction in the shift amount Δx(n) in the main scanningdirection with respect to a pixel position n shown in FIG. 25A, or thesummation of squares of the differences between the existing positionshift amounts in the main scanning direction and the new position shiftamounts in the main scanning direction may be applied. The differencebetween the existing position shift amount in the main scanningdirection and the new position shift amount in the main scanningdirection may be calculated by subtracting the existing position shiftamount in the main scanning direction from the new position shift amountin the main scanning direction.

As the index indicating the difference between the existing headvibration error according to the carriage movement and the new headvibration error according to the carriage movement, the summation of theratios between the existing position shift amounts in the main scanningdirection and the new position shift amounts in the main scanningdirection in the shift amount Δx(n) in the main scanning direction inthe pixel position n shown in FIG. 25A, or the summation of squares ofthe ratios between the existing position shift amounts in the mainscanning direction and the new position shift amounts in the mainscanning direction may be applied. The ratio between the existingposition shift amount in the main scanning direction and the newposition shift amount in the main scanning direction may be calculatedby dividing the new position shift amount in the main scanning directionby the existing position shift amount in the main scanning direction.

A shift amount Δy(n) in the sub scanning direction with respect to apixel position n shown in FIG. 25B may be applied instead of the shiftamount Δx(n) in the main scanning direction with respect to the pixelposition n or together with the shift amount Δx(n) in the main scanningdirection with respect to the pixel position n.

As the specified value in a case where the head vibration erroraccording to the carriage movement is the characteristic parameter, anindex indicating similarity may be applied. As the similarity, acorrelation coefficient may be applied. The specified value in a casewhere the head vibration error according to the carriage movement is thecharacteristic parameter may be determined based on the magnitude of thehead vibration error according to the carriage movement. As themagnitude of the head vibration error according to the carriagemovement, a standard deviation or a variance of the magnitude of thehead vibration error according to the carriage movement may be applied.The head vibration error according to the carriage movement correspondsto the head vibration error.

As another example of the characteristic parameter to be updated, thereis a head module (denoted by reference numeral 220-j (=1, 2, . . . , andNm) in FIG. 28) vibration error which is the characteristic parameterspecific to the single path type.

As the specified value in a case where the head module vibration errorin the single path type is the characteristic parameter, an indexindicating the difference between the existing head module vibrationerror and the new head module vibration error may be applied. As theindex indicating the difference between the existing head modulevibration error and the new head module vibration error, the summationof the absolute values of the difference between the existing positionshift amounts in the main scanning direction and the new position shiftamounts in the main scanning direction, or the summation of squares ofthe differences between the existing position shift amounts in the mainscanning direction and the new position shift amounts in the mainscanning direction in the position shift amount (dot position shiftamount) in the main scanning direction (denoted by reference numeral x)with respect to the position in the paper transport direction (subscanning direction, denoted by reference numeral y) shown in FIG. 28 maybe applied.

The difference between the existing position shift amount in the mainscanning direction and the new position shift amount in the mainscanning direction may be calculated by subtracting the existingposition shift amount in the main scanning direction from the newposition shift amount in the main scanning direction.

As the index indicating the difference between the existing head modulevibration error and the new head module vibration error, the summationof the ratios between the existing position shift amounts in the mainscanning direction and the new position shift amounts in the mainscanning direction or the summation of squares of the ratios between theexisting position shift amounts in the main scanning direction and thenew position shift amounts in the main scanning direction in theposition shift amount (dot position amount) in the main scanningdirection (denoted by reference numeral x) with respect to the positionin the paper transport direction (sub scanning direction, denoted byreference numeral y) shown in FIG. 28 may be applied.

The ratio between the existing position shift amount in the mainscanning direction and the new position shift amount in the mainscanning direction may be calculated by dividing the new position shiftamount in the main scanning direction by the existing position shiftamount in the main scanning direction.

As the specified value in a case where the head module vibration errorin the single path type is the characteristic parameter, the indexindicating the similarity between the existing head module vibrationerror and the new head module vibration error may be applied. As theindex indicating the similarity between the existing head modulevibration error and the new head module vibration error, the correlationcoefficient may be applied. The head module vibration error correspondsto the head module vibration error in the head including by a pluralityof head modules.

The specified value in a case where the head module vibration error isthe characteristic parameter may be determined based on the magnitude ofthe head module vibration error. As the magnitude of the head modulevibration error, a standard deviation or a variance of the magnitude ofthe head module vibration error may be applied.

In the printing system according to the present embodiment, at least anyone characteristic parameter of the above-described characteristicparameters may be updated.

<Modification Example of Printing System According to Fourth Embodiment>

FIG. 41 is a flowchart of a method of generating the halftone processingrule applied to a modification example of the printing system accordingto the fourth embodiment. In FIG. 41, the same steps as those of FIG. 38will be assigned the same reference numerals, and the descriptionthereof will be appropriately omitted.

The characteristic parameter in the method of generating the halftoneprocessing rule shown in FIG. 38 may be updated whenever the print jobis executed. The characteristic parameter shown in the flowchart of FIG.38 may be updated during the execution of the print job. However, in acase where the characteristic parameter is updated during the executionof the print job, it is preferable that the halftone processing rule isdetermined such that the printing is not stopped when the user selectsthe halftone processing rule.

The flowchart shown in FIG. 41 includes a halftone-processing-ruledetermination step S110 of determining the halftone processing rulebased on the priority parameter, instead of the halftone-selection-chartoutput step S107 and the halftone selection operating step S108 in theflowchart shown in FIG. 38.

The halftone-processing-rule determination step S110 shown in FIG. 41has the same content as that of the step (step S17) of determining onekind of halftone processing rule from the two or more kinds of generatedhalftone processing rules based on the priority parameter after the twoor more kinds of halftone processing rules are generated as shown inFIG. 20, and thus, the description thereof will be omitted.

That is, in the flowchart shown in FIG. 37, if there is no userselection in the halftone selection operating step S108, there is aconcern that the printing is stopped without determining the halftoneprocessing rule to be applied to the printing. Meanwhile, in theflowchart shown in FIG. 41, since the halftone processing rule isdetermined from the two or more kinds of halftone processing rules basedon the priority parameter in the halftone-processing-rule determinationstep S110, the phenomenon in which the printing is stopped withoutdetermining the halftone processing rule to be applied to the printingdoes not occur.

According to the printing system having the above-describedconfiguration, since the characteristic parameter is updated accordingto the difference between the existing characteristic parameter and thenew characteristic parameter, the characteristic parameter may beupdated according to the change of the characteristics of the printingsystem.

Since the halftone processing rule is generated using the updatedcharacteristic parameter, the printing using the halftone processingrule corresponding to the change of the characteristics of the printingsystem can be performed.

[Description of Output of Characteristic Parameter Acquisition Chart andGeneration of Halftone Processing Rule According to Fifth Embodiment]

Hereinafter, the output of the characteristic parameter acquisitionchart and the generation of the halftone processing rule according to afifth embodiment will be described.

<Flowchart of Method of Generating Halftone Processing Rule to whichOutput of Characteristic Parameter Acquisition Chart and Generation ofHalftone Processing Rule are Applied According to Fifth Embodiment>

FIG. 42 is a flowchart of a method of generating the halftone processingrule according to the fifth embodiment. The method of generating thehalftone processing rule of the flowchart shown in FIG. 42 may beapplied to the image processing device 20 shown in FIG. 3 and the imageprocessing device 20A shown in FIG. 37. In the following description, itis assumed that the characteristic parameter acquisition chart is outputand the halftone processing rule is generated during the execution of anarbitrary print job.

In the method of generating the halftone processing rule show in theflowchart of FIG. 42, the halftone processing rule used in theoutputting of the subsequent image to the image which is output togetherwith the characteristic parameter acquisition chart is generated basedon the characteristic parameter acquisition chart which is outputtogether with the image. The image subsequent to the image which isoutput together with the characteristic parameter acquisition chart maybe the next image of the plurality of images which is continuouslyoutput, or may be an image subsequent to the next image. The pluralityof images may have the same content, or may have different contents.

In an initialization step S120, zero is substituted for iA indicating animage number, and zero is substituted for jA indicating a halftoneprocessing rule number. That is, a first image of an arbitrary print jobis determined, and a halftone processing rule applied to the first imageis determined.

In the present embodiment, the values substituted for the image numberiA, the halftone processing rule number jA and a chart number kA arezero and a positive integer. In the following description, an iA-thimage is described as the image iA, a jA-th halftone processing rule isdescribed as the halftone processing rule jA, and a kA-th characteristicparameter acquisition chart is described as the characteristic parameteracquisition chart kA (chart kA). In FIG. 42, the characteristicparameter acquisition chart kA (chart kA) is not shown.

In an image output step S122, the halftone process is performed on imagedata indicating the image iA using the halftone processing rule jA, andthe image iA is output. The halftone process is performed by thehalftone processing unit 80 shown in FIG. 3. The image is output by theimage processing device 20 shown in FIG. 1. The halftone processing unit80 corresponds to halftone processing means.

In a determination step S124, it is determined whether or not theoutputting of the entire image iA is completed. In a case where it isdetermined as Yes in the determination step S124, that is, theoutputting of the entire image iA is completed, the step proceeds to anending step. In a case where it is determined as No in the determinationstep S124, that is, the outputting of the entire image iA is notcompleted, the step proceeds to acharacteristic-parameter-acquisition-chart output step S126.

In the characteristic-parameter-acquisition-chart output step S126, thecharacteristic parameter acquisition chart is output together with theimage iA. As the aspect in which the characteristic parameteracquisition chart is output together with the image iA, there is anaspect in which the characteristic parameter acquisition chart is outputon a part of the paper on which the image iA is printed (see FIG. 43A).

If the characteristic parameter acquisition chart is output, the stepproceeds to a characteristic parameter acquisition step S128 ofacquiring the output characteristic parameter by reading the outputcharacteristic parameter acquisition chart and analyzing the read imageof the characteristic parameter acquisition chart. The characteristicparameter acquisition step S128 shown in FIG. 42 has the same contentsas those of the step (step S11) of reading the characteristic parameteracquisition chart shown in FIG. 4 and the step (step S12) of analyzingthe read image acquired in step S11 and acquiring the characteristicparameters related to the characteristics of the printing system, andthus, the description thereof will be omitted.

If the characteristic parameter is acquired, two or more kinds ofhalftone processing rules of which priorities of the requirements forthe halftone process are different are generated in a halftone processgeneration step S130. In a halftone-processing-rule determination stepS132, a halftone processing rule jA+1 is determined based on thepriority parameter.

The halftone process generation step S130 shown in FIG. 42 is the sameas the step (step S14) of generating the two or more kinds of halftoneprocessing rules of which the priorities of the requirements for thehalftone process shown in FIG. 4 are different. Thehalftone-processing-rule determination step S132 shown in FIG. 42 hasthe same content as that of the step (step S17) of determining one kindof halftone processing rule based on the priority parameter shown inFIG. 20.

In an updating step S136, the image number is updated from iA to iA+1.The halftone processing rule number is updated from jA to jA+1. Theupdating of the image number includes both a case where the content ofthe image is changed and a case where the content of the image is notchanged. In a case where the halftone processing rule number is updatedfrom jA to jA+1, the halftone processing rule jA and the halftoneprocessing rule jA+1 may have the same content.

If the image number and the halftone processing rule number are updated,the step proceeds to the determination step S124, and the steps from thedetermination step S124 to the updating step S136 are repeatedlyperformed.

Although the aspect in which the determination step S124 is performed inthe next step to the image output step S122 has been described in FIG.42, the determination step S124 may be the next step to thecharacteristic-parameter-acquisition-chart output step S126, or may bethe next step to the halftone-processing-rule determination step S132.

FIG. 43A is a conceptual diagram of the method of generating thehalftone tone processing rule according to the fifth embodiment. HT inFIG. 43A denotes the halftone processing rule. The same is true of FIG.43B.

On the uppermost portion of FIG. 43A, the image iA output together withthe characteristic parameter acquisition chart (chart kA) isrepresented. The halftone process is performed on the image iA by usinga halftone processing rule jA(HTjA). A halftone processing rulejA+1(HTjA+1) is generated based on the characteristic parameteracquisition chart kA shown in FIG. 43A through the characteristicparameter acquisition step S128 and the halftone process generation stepS130 shown in FIG. 42. The halftone processing rule jA is generatedbased on a characteristic parameter acquisition chart (chart kA−1)output together with an image iA−1 (not shown).

On the middle portion of FIG. 43A, an image iA+1 output together with acharacteristic parameter acquisition chart (chart kA+1) is represented.The halftone process is performed on the image iA+1 by using thehalftone processing rule jA+1(HTjA+1) generated based on thecharacteristic parameter acquisition chart kA.

A halftone processing rule jA+2(HTjA+2) is generated based on thecharacteristic parameter acquisition chart kA+1 shown in FIG. 43Athrough the characteristic parameter acquisition step S128 and thehalftone process generation step S130 shown in FIG. 42.

On the bottommost portion of FIG. 43A, an image iA+2 output togetherwith the characteristic parameter acquisition chart (chart kA+2) isrepresented. The halftone process is performed on the image iA+2 byusing the halftone processing rule jA+2(HTjA+2) generated based on thecharacteristic parameter acquisition chart kA+1.

A halftone processing rule jA+3(HTjA+3) is generated based on thecharacteristic parameter acquisition chart kA+2 shown in FIG. 43Athrough the characteristic parameter acquisition step S128 and thehalftone process generation step S130 shown in FIG. 42.

According to the method of generating the halftone processing ruleaccording to the fifth embodiment, since a characteristic parameteracquisition chart used to generate a halftone processing rule used in asubsequently output image is output together with the image during theexecution of an arbitrary print job, it is possible to determine thechange of the characteristics of the printing system whenever the imageis output (whenever the characteristic parameter acquisition chart isoutput), and it is possible to generate the halftone processing rulecorresponding to the change of the characteristics of the printingsystem.

Accordingly, the image is output using the halftone processing rulecorresponding to the change of the characteristics of the printingsystem, and thus, it is possible to prevent the image quality from beingdeteriorated even in a case where the characteristics of the printingsystem are changed.

In FIG. 43A, the aspect in which the characteristic parameteracquisition chart is output on the same paper as the paper on which theimage is output has been described as the aspect in which thecharacteristic parameter acquisition chart is simultaneously output withthe image output. However, the characteristic parameter acquisitionchart may be output on a paper which is the subsequent paper to thepaper on which the image is output and is the paper before the nextimage is output.

<Application Example of Method of Generating Halftone Processing RuleAccording to Fifth Embodiment>

Hereinafter, an application example of the method of generating thehalftone processing rule according to the fifth embodiment will bedescribed. Any one or more processes of the process (output process) ofoutputting the characteristic parameter acquisition chart, the processof reading the characteristic parameter acquisition chart and acquiringthe characteristic parameter and the process of generating the halftoneprocessing rule, and the halftone process are performed in parallel byapplying the method of generating the halftone processing rule describedwith reference to FIGS. 42 and 43A. By doing this, it is possible toperform any one or more processes of the process of outputting thecharacteristic parameter acquisition chart, the process of reading thecharacteristic parameter acquisition chart and acquiring thecharacteristic parameter and the process of generating the halftoneprocessing rule and the halftone process within the same period of time.

FIG. 43B is a conceptual diagram of the method of generating thehalftone processing rule according to the application example of thefifth embodiment. In FIG. 43B, the same parts as those of FIG. 43A willbe assigned the same reference numerals, and the description thereofwill be appropriately omitted.

On the uppermost portion of FIG. 43B, the image iA output together withthe characteristic parameter acquisition chart (chart kA) isrepresented. The halftone process is performed on the image iA by usingthe halftone processing rule jA(HTjA). The characteristic parameteracquisition chart kA output together with the image iA is acharacteristic parameter acquisition chart used when the halftoneprocessing rule applied to the halftone process of the image iA+2 outputtwo images later than the image iA is generated.

The halftone processing rule jA+2(HTjA+2) is generated based on thecharacteristic parameter acquisition chart kA shown in FIG. 43B throughthe characteristic parameter acquisition step S128 and the halftoneprocess generation step S130 shown in FIG. 42.

On the middle portion of FIG. 43B, the image iA+1 output together withthe characteristic parameter acquisition chart (chart kA+1) isrepresented. The halftone process is performed on the image iA+1 byusing the halftone processing rule jA+1(HTjA+1) generated based on thecharacteristic parameter acquisition chart kA−1 (not shown).

The halftone processing rule jA+3(HTjA+3) is generated based on thecharacteristic parameter acquisition chart kA+1 shown in FIG. 43Bthrough the characteristic parameter acquisition step S128 and thehalftone process generation step S130 shown in FIG. 42.

On the bottom portion of FIG. 43B, the image iA+2 output together withthe characteristic parameter acquisition chart (chart kA+2) isrepresented. The halftone process is performed on the image iA+2 byusing the halftone processing rule jA+2(HTjA+2) generated based on thecharacteristic parameter acquisition chart kA.

A halftone processing rule jA+4(HTjA+4) is generated based on thecharacteristic parameter acquisition chart kA+2 shown in FIG. 43Bthrough the characteristic parameter acquisition step S128 and thehalftone process generation step S130 shown in FIG. 42.

That is, in the method of generating the halftone processing rule shownin FIG. 43B, the characteristic parameter acquisition chart used togenerate the halftone processing rule used in the halftone process isoutput together with an image output two images earlier than the imageon which the halftone process is performed. In other words, the halftoneprocess generation unit 58 (see FIG. 37) generates the halftoneprocessing rule by using the characteristic parameter acquisition charttogether with an image output two images earlier than the image on whichthe halftone process is performed.

In FIG. 43B, the aspect in which the characteristic parameteracquisition chart used to generate the halftone processing rule used inthe halftone process is output together with an image output two imagesearlier than the image on which the halftone process is performed hasbeen described. However, the characteristic parameter acquisition chartused to generate the halftone processing rule used in the halftoneprocess may be output together with an image output two or more imagesearlier than the image on which the halftone process is performed.

Accordingly, it is possible to generate the halftone processing rulejA+2 applied to the halftone process of the image iA+2 based on thecharacteristic parameter acquisition chart kA during a period of timewhen the halftone process is performed on the image iA+1.

As in the method of generating the halftone processing rule shown inFIG. 43B, in a case where the halftone processing rule used in thehalftone process of an image output two or more images later than theimage output together with the characteristic parameter acquisitionchart is generated, the halftone process of an image output one imagelater than the image and the generation of the halftone processing ruleused in the halftone process of an image output two or more images laterthan the image may be simultaneously performed as parallel processes. Inother words, in a case where nB is an integer of 2 or more, and also ina case where a halftone processing rule jA+nB is generated from thecharacteristic parameter acquisition chartkA output together with theimage iA which is the processing result of the halftone process by usingthe halftone processing rule jA, it is possible to simultaneouslyperform the halftone process and the generation of the halftoneprocessing rule as the parallel processes, and it is possible to improveproductivity. However, since the halftone processing rule is notgenerated based on the characteristic parameter acquisition chart outputtogether with the image from Halftone Processing Rule 1 to HalftoneProcessing Rule nB−1, Halftone Processing Rule 0 (initially set halftoneprocessing rule) is applied.

FIG. 44 is a flowchart of the method of generating the halftoneprocessing rule according to the application example of the fifthembodiment. In FIG. 44, the same steps as those of FIG. 42 will beassigned the same reference numerals, and the description thereof willbe appropriately omitted.

In an initialization step S121 shown in FIG. 44, zero is substituted foriA indicating the image number, zero is substituted for jA indicatingthe halftone processing rule number, and zero is substituted for thecharacteristic parameter acquisition chart number kA.

An image output step S122 and a determination step S124 shown in FIG. 44are the same as the image output step S122 and the determination stepS124 shown in FIG. 42, and the description thereof will be omitted.

In a case where it is determined as No in the determination step S124shown in FIG. 44 (the outputting of the entire image iA is notcompleted), the step proceeds to acharacteristic-parameter-acquisition-chart output step S140 and ahalftone processing step S148. In thecharacteristic-parameter-acquisition-chart output step S140, thecharacteristic parameter acquisition chart kA is output together withthe image iA.

In a characteristic parameter acquisition step S142, the characteristicparameter acquisition chart kA output in thecharacteristic-parameter-acquisition-chart output step S140 is read, andthe characteristic parameter is acquired.

In a halftone process generation step S144, two or more kinds ofhalftone processing rules of which the requirements are different aregenerated based on the characteristic parameter acquired in thecharacteristic parameter acquisition step S142.

In a halftone-processing-rule determination step S146, the halftoneprocessing rule jA+2 applied to the halftone process of the image iA+2is determined from the two or more kinds of halftone processing rules ofwhich the requirements are different and which are generated in thehalftone process generation step S144 based on the priority parameter.The halftone processing rule jA+2 is stored in thehalftone-processing-rule storage unit shown in FIG. 3 or 37(halftone-processing-rule storing step).

In a halftone processing step S148, the halftone process is performedusing the halftone processing rule jA+1, and the image iA+1 is output.The halftone processing rule jA+1 is an initially set halftoneprocessing rule (Halftone Processing Rule 0) in a case where jA=0, andis a halftone processing rule generated based on the characteristicparameter acquisition chart kA−1 output together with the image iA−1 ina case where jA>0.

In the method of generating the halftone processing rule shown in FIG.44, the halftone processing step S148 may be performed within the sameperiod of time as that of the characteristic-parameter-acquisition-chartoutput step S140, the characteristic parameter acquisition step S142,the halftone process generation step S144 and thehalftone-processing-rule determination step S146, which are a series ofsteps of generating the halftone processing rule, and the halftoneprocessing rule jA+2 applied to the halftone process of the image iA+2in parallel with the halftone process of the image iA+1 may begenerated.

In an updating step S150, the image number is updated from iA to iA+1.The halftone processing rule number is updated from jA to jA+1. Thecharacteristic parameter acquisition chart number is updated from kA tokA+1.

According to the method of generating the halftone processing ruleaccording to the application example of the fifth embodiment having theabove-described configuration, the halftone process and the generatingof the halftone processing rule are performed in parallel, and thus, itis possible to improve the productivity of the printing system unlike acase where the generation of the halftone processing rule that reflectsthe change of the characteristics of the printing system and thehalftone process to which the halftone processing rule that reflects thechange of the characteristics of the printing system is applied aresuccessively performed.

<Description of Modification Example of Method of Generating HalftoneProcessing Rule According to Application Example of Fifth Example>

FIG. 45 is a flowchart of a first modification example of the method ofgenerating the halftone processing rule according to the applicationexample of the fifth embodiment. FIG. 46 is a flowchart of a secondmodification example of the method of generating the halftone processingrule according to the application example of the fifth embodiment. InFIGS. 45 and 46, the same steps as those of FIG. 44 will be assigned thesame reference numerals, and the description thereof will beapproximately omitted.

As shown in FIGS. 45 and 46, the methods of generating the halftoneprocessing rule shown in FIG. 44 may be changed in consideration of thebalance of parallel processes. As the balance of parallel processes,there are the balance of processing time and the balance of processingload.

In the method of generating the halftone processing rule according tothe first modification example shown in FIG. 45, the halftone processgeneration step S144 and the halftone-processing-rule determination stepS146 of the method of generating the halftone processing rule shown inFIG. 44 are removed, a characteristic parameter storing step S143 isadded after the characteristic parameter acquisition step S142, and ahalftone process generation step S154 and a halftone-processing-ruledetermination step S156 are added before the halftone processing stepS148.

In the method of generating the halftone processing rule shown in FIG.45, if the characteristic parameter used when the halftone processingrule jA+2 is generated is acquired based on the characteristic parameteracquisition chart kA in the characteristic parameter acquisition stepS142, the characteristic parameter is stored in the characteristicparameter storing step S143, and the step proceeds to an updating stepS150. The characteristic parameter is stored in the characteristicparameter storage unit 54 shown in FIG. 3.

In a case where it is determined as No (the outputting of the entireimage iA is not completed) in the determination step S124 shown in FIG.45, the step proceeds to the characteristic-parameter-acquisition-chartoutput step S140 and the halftone process generation step S154. In thehalftone process generation step S154, two or more kinds of halftoneprocessing rules of which the priorities of the requirements aredifferent are generated based on the characteristic parameter acquiredfrom the characteristic parameter acquisition chart kA−1 output togetherwith the image iA−1 (the previous image of the image iA).

In the halftone-processing-rule determination step S156, the halftoneprocessing rule jA+1 applied to the halftone process of the image iA+1is generated from two or more kinds of halftone processing rules ofwhich the priorities of the requirements are different and which aregenerated in the halftone process generation step S154 based on thepriority parameter.

In the halftone processing step S148, the halftone process is performedusing the halftone processing rule jA+1 determined in thehalftone-processing-rule determination step S156, and the image iA+1 isoutput. If the image iA+1 is output in the halftone processing step S148and the characteristic parameter used when the halftone processing rulejA+2 is generated is stored in the characteristic parameter storing stepS143, the step proceeds to the updating step S150.

In a case where the first image is output, the halftone processgeneration step S154 and the halftone-processing-rule determination stepS156 are omitted, and a process of “performing the halftone process byusing Halftone Processing Rule 0 and outputting Image 1” is performedinstead of the halftone processing step S148.

In the method of generating the halftone processing rule according tothe second modification example shown in FIG. 46, thecharacteristic-parameter-acquisition-chart output step S140 ofoutputting the characteristic parameter acquisition chart kA togetherwith the image iA is performed as the step which is performed after theimage output step S122 of the method of generating the halftoneprocessing rule shown in FIG. 44 and is performed before thedetermination step S124.

In the method of generating the halftone processing rule shown in FIG.46, the characteristic parameter acquisition chart is output togetherwith the first image. The image output step S122 and thecharacteristic-parameter-acquisition-chart output step S140 shown inFIG. 46 may be performed as one step.

In a case where it is determined as No in the determination step S124shown in FIG. 46 (the outputting of the entire image iA is notcompleted), the step proceeds to the characteristic parameteracquisition step S142 and the halftone processing step S148.

If the image iA+1 is output in the halftone processing step S148, thestep proceeds to the characteristic-parameter-acquisition-chart outputstep S160. In the characteristic-parameter-acquisition-chart output stepS160, the characteristic parameter acquisition chart kA+1 is outputtogether with the image iA+1.

In the updating step S162 which is provided instead of the updating stepS150 shown in FIG. 44 and is shown in FIG. 46, the image number isupdated from iA to iA+1. The halftone processing rule number is updatedfrom jA to jA+1. The characteristic parameter acquisition chart numberis updated from kA to kA+1.

The method of generating the halftone processing rule shown in FIGS. 44,45 and 46 is a method of generating the halftone processing rule forperforming the halftone process on an image output two images later thanthe image output together with the characteristic parameter acquisitionchart based on the characteristic parameter acquisition chart. However,an integer of 2 or more is expressed as nB, and a halftone processingrule for performing the halftone process on an image output later thanan nB-th image may be similarly generated.

Specifically, in the halftone-processing-rule determining step S146shown in FIGS. 44 and 46, a “halftone processing rule jA+nB” may bedetermined instead of the “halftone processing rule jA+2”. In the methodof generating the halftone processing rule shown in FIG. 45, a “halftoneprocessing rule jA+nB−1” may be determined instead of the “halftoneprocessing rule jA+1” in the halftone-processing-rule determining stepS156. The same is not true of the halftone processing step S148 shown inFIGS. 44, 45 and 46.

However, in the method of generating the halftone processing rule shownin FIGS. 44, 45 and 46, since the halftone processing rule is notgenerated from Halftone Processing Rule 1(jA=1) to Halftone ProcessingRule nB−1 based on the characteristic parameter acquisition chart outputtogether with the image output, the halftone process is performed usingHalftone Processing Rule 0 (initially set halftone processing rule)instead of the halftone processing rule jA+1 in the halftone processingstep S148. In the method of generating the halftone processing ruleshown in FIG. 45, the halftone process generation step S154 and thehalftone-processing-rule determining step S156 are omitted.

In the method of generating the halftone processing rule shown in FIGS.42, 44, 45 and 46, the images and the halftone processing rules are inone-to-one correspondence. That is, if the image is changed, thehalftone processing rule is changed. However, it is not necessary tonecessarily perform such a change. One halftone processing rule may beapplied to a plurality of images. For example, Halftone Processing Rule1 may be applied to Image 1, Image 2, Image 3 and Image 4, and HalftoneProcessing Rule 2 may be applied to Image 5, Image 6, Image 7 and Image8.

That is, the halftone processing rule is updated once at a time wheneverthe plurality of images is output, and thus, it is possible to improvethe productivity. In a case where the halftone processing rule isupdated once at a time whenever the plurality of images is output, thecharacteristic parameter acquisition chart may be output together withany one of the plurality of images.

Since the image together with the characteristic parameter acquisitionchart and the image on which the halftone process is performed using thehalftone processing rule generated based on this characteristicparameter acquisition chart are separated with two or more imagesinterposed therebetween, the halftone process and the generation of thehalftone processing rule are simultaneously performed as the parallelprocesses, and thus, it is possible to further improve the productivityas described above.

According to the methods of generating the halftone processing ruleaccording to the first modification and the second modification, it ispossible to obtain the same effects as those of the method of generatingthe halftone processing rule according to the application example of thefifth embodiment, and it is possible to optimize the allocation of theprocessing time of the parallel processes and the allocation of theprocessing load of the parallel processes depending on the configurationof the printing system.

[Description of Outputting of Characteristic Parameter Acquisition ChartAccording to Sixth Embodiment]

<Configuration of Image Processing Device>

FIG. 47 is a block diagram showing the configuration of an imageprocessing device applied to a printing system according to a sixthembodiment. For the sake of convenience in the illustration, in FIG. 47,control units 50 are shown in two places. The functions and structuresof the control units 50 in two places shown in FIG. 47 are not limited.In the acquisition of the characteristic parameter according to thesixth embodiment, a new characteristic parameter is acquired bygenerating the characteristic parameter acquisition chart based on thecharacteristic parameter related to the system specification retained ina characteristic parameter storage unit 54, outputting thecharacteristic parameter acquisition chart, reading the characteristicparameter acquisition chart and analyzing the read image of thecharacteristic parameter acquisition chart.

The characteristic parameters related to the system specifications aredetermined based on the system specification. In other words, thischaracteristic parameter is a characteristic parameter acquired withoutusing the characteristic parameter acquisition chart.

As an example of the characteristic parameter related to the systemspecification, there are a droplet kind, unidirectional scanning, orbidirectional scanning in addition to the resolution, the number ofnozzles (number of used nozzles) and the ink kind which are alreadydescribed. In the present embodiment, the characteristic parametersrelated to the system specifications are described as systemspecification parameters.

Among the characteristic parameters, the characteristic parameter otherthan the system specification parameter is a characteristic parameteracquired using the characteristic parameter acquisition chart.

As an example of the characteristic parameter other than the systemspecification parameter, there are a dot density, a dot diameter, a dotshape, a dot forming position shift, and non-jetting of each printingelement. As another example of the characteristic parameter other thanthe system specification parameter, an average dot density, an averagedot diameter and an average dot shape of the plurality of printingelements. As another example of the characteristic parameter other thanthe system specification parameter, a dot forming position shift foreach droplet kind, a bidirectional printing position shift, a headvibration error, a transport error of the printing medium, a head modulevibration error in a head formed using a plurality of head modules, andlanding interference.

Here, the characteristic parameter acquisition chart corresponding tothe acquired system specification parameter may be selected from thecharacteristic parameter acquisition charts stored in acharacteristic-parameter-acquisition-chart storage unit 242 instead ofgenerating the characteristic parameter acquisition chart.

The characteristic parameter storage unit 54 corresponds tocharacteristic parameter storage means. Acharacteristic-parameter-acquisition-chart generation unit 62corresponds to characteristic-parameter-acquisition-chart generationmeans. The configuration in which the characteristic parameteracquisition chart is selected instead of generating the characteristicparameter acquisition chart using thecharacteristic-parameter-acquisition-chart generation unit 62corresponds to characteristic-parameter-acquisition-chart selectionmeans. The characteristic-parameter-acquisition-chart storage unit 242corresponds to characteristic-parameter-acquisition-chart storage means.

In the following embodiment, an aspect in which the characteristicparameter acquisition chart is generated or selected according to theselection of a printing mode will be described.

An image processing device 21 shown in FIG. 47 is configured such that aprinting mode selection unit 240, thecharacteristic-parameter-acquisition-chart storage unit 242, and achart-output-condition setting unit 244 are added to the imageprocessing device 20 shown in FIG. 3.

The printing mode selection unit 240 selects a printing mode in theprinting executed by a data output unit 66 and the printing device 24shown in FIG. 1. As a selection example of the printing mode, there arean aspect in which an operator selects the printing mode through theinput device 34 shown in FIG. 3, and an aspect in which the printingmode is automatically selected from information such as the kind ofprinting medium or input image data.

If the printing mode is selected, the system specification parametercorresponding to the selected printing mode is read and acquired fromthe system specification parameters stored in the characteristicparameter storage unit 54. Thecharacteristic-parameter-acquisition-chart generation unit 62 generatesthe characteristic parameter acquisition chart based on the acquiredsystem specification parameter.

If the characteristic parameter acquisition chart is generated, a chartoutput condition for the printing mode selected by thechart-output-condition setting unit 244 is set, and the characteristicparameter acquisition chart is output by the data output unit 66 and theprinting device 24 shown in FIG. 1.

Instead of generating the characteristic parameter acquisition chart,the characteristic parameter acquisition chart corresponding to theacquired system specification parameter may be selected from thecharacteristic parameter acquisition charts previously stored in thecharacteristic-parameter-acquisition-chart storage unit 242.

<Specification Example of Generation and Selection of CharacteristicParameter Acquisition Chart>

Hereinafter, a specific example of the selection of the characteristicparameter acquisition chart will be described. Unit charts eachincluding the single dot pattern and the continuous dot pattern aregenerated by the characteristic-parameter-acquisition-chart generationunit 62 shown in FIG. 47. The unit chart is a unit chart constitutingthe characteristic parameter acquisition chart, and is a necessityminimum chart. As an example of the single dot pattern in the serialscan type, there are the single dot patterns 102C, 102M, 102Y and 102Kshown in FIG. 5. As an example of the single dot pattern in the singlepath type, the single dot patterns 202C, 202M, 202Y and 202K shown inFIG. 21.

As an example of the continuous dot pattern in the serial scan type,there are the first continuous dot patterns 104C, 104M, 104Y and 104Kand the second continuous dot patterns 106C, 106M, 106Y and 106K shownin FIG. 5. As an example of the continuous dot pattern in the singlepath type, there are the first continuous dot patterns 204C, 204M, 204Yand 204K and the second continuous dot patterns 206C, 206M, 206Y and206K shown in FIG. 21.

If the printing mode is selected by the printing mode selection unit 240shown in FIG. 47, the characteristic parameter acquisition chartappropriate for the system specification parameter corresponding to theprinting mode is generated by generating the unit charts by thecharacteristic-parameter-acquisition-chart generation unit 62 andarranging the unit charts generated based on the system specificationparameter corresponding to the selected printing mode.

The generated characteristic parameter acquisition chart is stored inthe characteristic-parameter-acquisition-chart storage unit 242 by usingthe printing mode or the system specification parameter as an index.When the printing mode is selected, in a case where there is thecharacteristic parameter acquisition chart capable of being applied tothe selected printing mode or the characteristic parameter acquisitionchart capable of being applied to the system specification parametercorresponding to the selected printing mode, the characteristicparameter acquisition chart capable of being applied to the selectedprinting mode or the characteristic parameter acquisition chart capableof being applied to the system specification parameter corresponding tothe printing mode is selected instead of generating the characteristicparameter acquisition chart described above.

<Specific Example of Printing Mode and System Specification ParameterCorresponding to Printing Mode>

(1) In a case where a high-quality mode is selected, the ink kinds usedin the high-quality mode are cyan, magenta, yellow, black, light cyanand light magenta, the used droplet kind is only the small droplet, andthe scanning direction is the unidirectional scanning,

a chart is generated by arranging the unit charts of the small dropletof the cyan ink, the small droplet of the magenta ink, the small dropletof the yellow ink, the small droplet of the black ink, the small dropletof the light cyan ink and the small droplet of the light magenta ink aregenerated only in the outward scanning direction. A continuous dotpattern acquired by combining the small droplet of the cyan ink, thesmall droplet of the magenta ink, the small droplet of the yellow ink,the small droplet of the black ink, the small droplet of the light cyanink and the small droplet of the light magenta ink may be generated.

In a case where the characteristic parameter acquisition chart in a casewhere the ink kinds in the high-quality mode are cyan, magenta, yellow,black, light cyan and light magenta, the droplet kind is only the smalldroplet and the scanning direction is the unidirectional scanning isstored in the characteristic-parameter-acquisition-chart storage unit242, the characteristic parameter acquisition chart in a case where theink kinds in the high-quality mode are cyan, magenta, yellow, black,light cyan and light magenta, the droplet kind is only the small dropletand the unidirectional scanning is used is selected.

(2) In a case where a standard-quality mode is selected, the ink kindsused in the standard-quality mode are cyan, magenta, yellow and black,the used droplet kinds are the small droplet, the medium droplet and thelarge droplet and the scanning direction is the bidirectional scanning,

the unit charts for the small droplets, the medium droplets and thelarge droplets of the respective color inks of cyan, magenta, yellow andblack are generated, and the characteristic parameter acquisition chartacquired by arranging the generated unit charts in the outward scanningdirection and the inward scanning direction is generated. A continuousdot pattern acquired by combining the small droplets, the mediumdroplets and the large droplets of the respective color inks of cyan,magenta, yellow and black may be generated.

In a case where the characteristic parameter acquisition chart in a casewhere the ink kinds in the standard-quality mode are cyan, magenta,yellow and black, the used droplet kinds are the small droplet, themedium droplet and the large droplet and the scanning direction is thebidirectional scanning is stored in thecharacteristic-parameter-acquisition-chart storage unit 242, thecharacteristic parameter acquisition chart in a case where the ink kindsin the standard-quality mode are cyan, magenta, yellow and black, theused droplet kinds are the small droplet, the medium droplet and thelarge droplet and the scanning direction is the bidirectional scanningis selected.

(3) In a case where a monochrome mode is selected, the ink kind used inthe monochrome mode is only black, the used droplet kinds are the smalldroplet, the medium droplet and the large droplet and the scanningdirection is the bidirectional scanning,

the characteristic parameter acquisition chart acquired by generatingthe unit charts of the small droplet, the medium droplet and the largedroplet of the black ink and arranging the generated unit charts in theoutward scanning direction and the inward scanning direction isgenerated. A continuous dot pattern acquired by combining the smalldroplet, the medium droplet and the large droplet of the black ink maybe generated.

In a case where the characteristic parameter acquisition chart in a casewhere the ink kind in the monochrome mode is black, the used dropletkinds are the small droplet, the medium droplet and the large dropletand the scanning direction is the bidirectional scanning is stored inthe characteristic-parameter-acquisition-chart storage unit 242, thecharacteristic parameter acquisition chart in a case where the ink kindin the monochrome mode is black, the used droplet kinds are the smalldroplet, the medium droplet and the large droplet and the scanningdirection is the bidirectional scanning is selected.

In a case where the nozzles used by the printing mode are different, thecontents of the unit charts are different for the respective printingmodes. When the characteristic parameter acquisition chart is output,the chart-output-condition setting unit 244 sets a scanning speed, apaper transport amount and a jetting frequency corresponding to theselected printing mode, as the chart output condition. The scanningspeed is a speed of the recording head when the recording head scans inthe main scanning direction. The transport amount of the printing mediumis a distance at which the printing medium is moved while transport inthe sub scanning direction is performed once, and is a value byrepresenting an inverse number of a substantial resolution in the subscanning direction as a unit.

<Relationship Between Generation and Selection of CharacteristicParameter Acquisition Chart>

In a case where the storage capacity of thecharacteristic-parameter-acquisition-chart storage unit 242 shown inFIG. 47 is sufficient, the charts corresponding to the systemspecification parameters may be previously generated and stored for therespective printing modes.

Meanwhile, in a case where the storage capacity of thecharacteristic-parameter-acquisition-chart storage unit 242 shown inFIG. 47 is insufficient, in a case where there is a heavy cost burdenfor what the characteristic-parameter-acquisition-chart storage unit 242has the sufficient storage capacity, and in a case where a period oftime when the characteristic parameter acquisition chart is generated isa short period of time, the characteristic parameter acquisition chartmay be generated.

The characteristic parameter acquisition chart may be previouslygenerated and stored for the frequently selected printing mode, and thecharacteristic parameter acquisition chart may be generated sometimesfor the infrequently selected printing mode.

For example, in a printing mode selected when the printing isarbitrarily executed, the characteristic parameter acquisition chart forthe selected printing mode may be generated, and the generatedcharacteristic parameter acquisition chart may be stored in thecharacteristic-parameter-acquisition-chart storage unit 242 shown inFIG. 47 for a predetermined period of time. In a case where the sameprinting mode is reselected for a predetermined period of time, thecharacteristic parameter acquisition chart for the printing mode whichis stored in the characteristic-parameter-acquisition-chart storage unit242 is selected, and the characteristic parameter acquisition chart forthe printing mode is stored for a predetermined period of time from apoint of time when the printing mode is reselected. After thepredetermined period of time elapses, the characteristic parameteracquisition chart is deleted. After the characteristic parameteracquisition chart is deleted, the characteristic parameter acquisitionchart is newly generated when the printing mode is subsequently set, andis stored for a predetermined period of time. As mentioned above, aperiod of time during which the characteristic parameter acquisitionchart is stored may be determined, and the generation and selection ofthe characteristic parameter acquisition chart may be switched dependingon the period of time during which the characteristic parameteracquisition chart is stored.

[Description of Acquisition of Characteristic Parameter According toSeventh Embodiment]

Hereinafter, the acquisition of a characteristic parameter according toa seventh embodiment will be described.

<Entire Configuration>

FIG. 48 is a block diagram showing the configuration of an imageprocessing device applied to a printing system according to the seventhembodiment. In FIG. 48, the same configurations as those of FIG. 3 willbe assigned the same reference numerals, and the description thereofwill be appropriately omitted.

An image processing device 20B shown in FIG. 48 is configured such thata printing mode selection unit 300, a chart-output-condition settingunit 302, and a characteristic-parameter-acquisition-chart storage unit304 are added to the image processing device 20 shown in FIG. 3.

The printing mode selection unit 300 selects the printing mode in theprinting executed by the data output unit 66 and the printing device 24shown in FIG. 1. As a selection example of the printing mode, there arean aspect in which the printing mode manually input by the operatorthrough the input device 34 shown in FIG. 3 is selected, and an aspectin which the printing mode is automatically selected from informationsuch as the kind of printing medium or input image data. The printingmode selection unit 300 corresponds to printing mode selection means.

The chart-output-condition setting unit 302 shown in FIG. 48 sets achart output condition of the selected printing mode. The chart outputcondition includes at least one of a chart item related to the contentof the characteristic parameter acquisition chart or a scanningcondition related to the operations of the data output unit 66 and theprinting device 24 shown in FIG. 1. The details of the relationshipbetween the printing mode and the chart item and the relationshipbetween the printing mode and the scanning condition will be describedbelow. The chart-output-condition setting unit 302 corresponds tochart-output-condition setting means.

A characteristic-parameter-acquisition-chart generation unit 62 shown inFIG. 48 generates the characteristic parameter acquisition chart basedon the chart item set depending on the selected printing mode. Thecharacteristic parameter acquisition chart generated by thecharacteristic-parameter-acquisition-chart generation unit 62 is storedin the characteristic-parameter-acquisition-chart storage unit 304. Whenthe characteristic parameter acquisition chart is output, thecharacteristic parameter acquisition chart corresponding to the setchart output condition may be selectively read from thecharacteristic-parameter-acquisition-chart storage unit 304.

That is, in the acquisition of the characteristic parameter according tothe seventh embodiment, the chart output condition when thecharacteristic parameter acquisition chart is acquired depending on theprinting mode is set. As the chart output condition, at least any one ofthe chart item related to the content of the characteristic parameteracquisition chart or a scanning condition related to the operation ofthe printing device 24 which functions as a part of acharacteristic-parameter-acquisition-chart output means and is shown inFIG. 1 is set.

<Description of Printing Mode>

FIG. 49 is an explanatory diagram of the printing mode. In the presentembodiment, an example in which the printing device 24 shown in FIG. 1is an ink jet recording device including serial scan type recordingheads will be described. The serial scan type recording heads areassigned the reference numerals 112C, 112M, 112Y and 112K in FIG. 6.

The recording head applied to the present embodiment has a structure inwhich 50 nozzles are arranged with an arrangement density of 150 nozzlesper inch. The nozzles are assigned the reference numerals 118C, 118M,118Y and 118K in FIG. 6. However, the number of nozzles and the nozzledensity described above are examples, and the printing system accordingto the present embodiment is not limited thereto.

As shown in FIG. 49, the printing system according to the presentembodiment may select 7 kinds of printing modes. If the printing mode isselected, the chart output condition is set. In FIG. 49, as an exampleof the chart output condition, the ink kind, the resolution, the dropletkind, the number of paths in the main scanning direction, the scanningspeed, the frequency, the unidirectional scanning or the bidirectionalscanning, the nozzle, and the transport amount are illustrated. As thenames of a horizontal series of items shown in FIG. 49, abbreviationterms are used. For example, uni/bi shown in FIG. 49 represents theunidirectional scanning or the bidirectional scanning. The chart outputcondition is not limited to the condition shown in FIG. 49, and may beadded, deleted and changed depending on the specification of theprinting system.

The ink kind as the chart output condition shown in FIG. 49 representsthe kind of ink used in each printing mode. C represents the cyan ink,Lc represents the light cyan ink, M represents the magenta ink, Lmrepresents the light magenta ink, Y represents the yellow ink, and Krepresents the black ink. The ink is one aspect of a liquid.

In Printing Mode A, only the black ink is used. In Printing Mode B,Printing Mode C and Printing Mode D, 4 kinds of inks such as the cyanink, the magenta ink, the yellow ink and the black ink are used. InPrinting Mode E, Printing Mode F and Printing Mode G, 6 kinds of inkssuch as the cyan ink, the light cyan ink, the magenta ink, the lightmagenta ink, the yellow ink and the black ink are used.

If Printing Mode A is selected, the characteristic parameter acquisitionchart is output using only the black ink. If Printing Mode B, PrintingMode C and Printing Mode D are selected, the characteristic parameteracquisition chart is output using 4 kinds of inks such as the cyan ink,the magenta ink, the yellow ink and the black ink. If Printing Mode E,Printing Mode F and Printing Mode G are selected, the characteristicparameter acquisition chart is output using 6 kinds of inks such as thecyan ink, the light cyan ink, the magenta ink, the light magenta ink,the yellow ink and the black ink.

In a case where the ink kind shown in FIG. 49 is limited by the printingmode, it is possible to output the characteristic parameter acquisitionchart by using the used ink, and it is possible to appropriately acquirethe characteristic parameter for each used ink kind.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired after the characteristicparameter acquisition chart is output.

The resolution as the chart output condition shown in FIG. 49 representsprinting resolution. In Printing Mode A and Printing Mode B, lowresolution is applied. As an example of the low resolution, there is anaspect in which the resolution in the main scanning direction is 150dots per inch and the resolution in the sub scanning direction is 150dots per inch.

In Printing Mode C and Printing Mode E, medium resolution is applied. Asan example of the medium resolution, there is an aspect in which theresolution in the main scanning direction is 300 dots per inch and theresolution in the sub scanning direction is 300 dots per inch.

In Printing Mode D and Printing Mode F, high resolution is applied. Asan example of the high resolution, there is an aspect in which theresolution in the main scanning direction is 600 dots per inch and theresolution in the sub scanning direction is 600 dots per inch.

In Printing Mode G, super-high resolution is applied. As an example ofthe super-high resolution, there is an aspect in which the resolution inthe main scanning direction is 1200 dots per inch and the resolution inthe sub scanning direction is 1200 dots per inch.

In a case where the resolution shown in FIG. 49 is determined by theprinting mode, it is possible to output the characteristic parameteracquisition chart by using the determined resolution, and it is possibleto appropriately acquire the characteristic parameter for the determinedresolution.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The droplet kind as the chart output condition shown in FIG. 49represents the kind of liquid droplet classified by a volume ratio. Inthe printing system shown in the present embodiment, 5 kinds of liquiddroplets such as extra-large, large, medium, small and extra-small areused. As an example of the droplet kind, there is an example in which avolume ratio of the extra-small droplet kind is 1, a volume ratio of thesmall droplet kind is 2, a volume ratio of the medium droplet kind is 4,a volume ratio of the large droplet kind is 8 and a volume ratio of theextra-large kind is 16.

The droplet kind is determined by the resolution in most cases. InPrinting Mode A and Printing Mode B to which the low resolution isapplied, 3 kinds of droplet kinds of medium, large and extra large areused. In Printing Mode C and Printing Mode E to which the mediumresolution is applied, 3 kinds of droplet kinds of small, medium andlarge are used. In Printing Mode D and Printing Mode F to which the highresolution is applied, 3 kinds of droplet kinds of extra-small, smalland medium are used. In Printing Mode G to which the super-highresolution is applied, one kind of droplet kind of extra-small is used.In FIG. 49, extra-large represents the extra-large droplet kind, andextra-small represents the extra-small droplet kind.

If Printing Mode A and Printing Mode B are selected, the characteristicparameter acquisition chart is output using 3 kinds of droplet kinds ofmedium, large and extra-large. If Printing Mode C and Printing Mode Eare selected, the characteristic parameter acquisition chart is outputusing 3 kinds of droplet kinds of small, medium and large. If PrintingMode D and Printing Mode F are selected, the characteristic parameteracquisition chart is output using 3 kinds of droplet kinds ofextra-small, small and medium. If Printing Mode G is selected, thecharacteristic parameter acquisition chart is output using one kind ofdroplet kind of extra-small.

In a case where the droplet kind shown in FIG. 49 is different by theprinting mode, it is possible to output the characteristic parameteracquisition chart by using the used droplet kind, and it is possible toappropriately acquire the characteristic parameter for the used dropletkind.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The number of paths as the chart output condition shown in FIG. 49represents the number of paths which is the number of times therecording head is moved in the main scanning direction which is requiredto arrange as much dots as one raster in the main scanning direction.The one raster in the main scanning direction is referred to as one linein the main scanning direction in some cases. In a case where the numberof paths is 2, as much of the dots as one raster are arranged byperforming the scanning in the main scanning direction twice. The errorof the landing position for each nozzle or the transport error of theprinting medium is diffused as the number of paths is increased, andthus, the high image quality is achieved.

As an example of the number of paths, the number of paths is 1 inPrinting Mode A and Printing Mode B to which the low resolution isapplied, and the number of paths is 2 in Printing Mode C and PrintingMode E to which the medium resolution is applied. In Printing Mode D andPrinting Mode F to which the high resolution is applied, the number ofpaths is 2. In Printing Mode G to which the super-high resolution isapplied, the number of paths is 4.

If Printing Mode A and Printing Mode B are selected, the characteristicparameter acquisition chart is output by setting the number of paths tobe 1. If Printing Mode C, Printing Mode D, Printing Mode E and PrintingMode F are selected, the characteristic parameter acquisition chart isoutput by setting the number of paths to be 2. If Printing Mode G isselected, the characteristic parameter acquisition chart is output bysetting the number of paths to be 4.

In a case where the number of paths shown in FIG. 49 is determined bythe printing mode, it is possible to output the characteristic parameteracquisition chart by using the determined number of paths, and it ispossible to appropriately acquire the characteristic parameter for thedetermined number of paths.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The scanning speed as the chart output condition shown in FIG. 49represents a scanning speed of the recording head in the main scanningdirection. The scanning speed shown in FIG. 49 represents a relativescanning speed ratio using a scanning speed in Printing Mode A andPrinting Mode B to which the low resolution is applied as a standardscanning speed. In FIG. 49, the standard scanning speed is representedas 1.

In Printing Mode C and Printing Mode E to which the medium resolution isapplied, a scanning speed of 1, that is, the standard scanning speed isapplied. In Printing Mode D and Printing Mode F to which the highresolution is applied, a scanning speed of 2, that is, a scanning speedwhich is twice as high as the standard scanning speed is applied. InPrinting Mode G to which the super-high resolution is applied, ascanning speed of 4, that is, a scanning speed which is four times ashigh as the standard scanning speed is applied.

If Printing Mode A, Printing Mode B, Printing Mode C and Printing Mode Eare selected, the characteristic parameter acquisition chart is outputat the standard scanning speed. If Printing Mode D and Printing Mode Fare selected, the characteristic parameter acquisition chart is outputat a scanning speed which is twice as high as the standard scanningspeed. If Printing Mode G is selected, the characteristic parameteracquisition chart is output at a scanning speed which is four times ashigh as the standard scanning speed.

The dot density, the dot diameter, the dot shape and the dot formingposition shift for each printing element, the position shift for eachdroplet kind, the landing interference, the bidirectional scanningposition shift of scanning in the serial scanning, and a bidirectionalprinting position shift of scanning for each droplet kind, and the headvibration error according to the carriage movement, which are acquiredas the characteristic parameters, are influenced by the scanning speed.

In a case where the scanning speed shown in FIG. 49 is determined by theprinting mode, it is possible to output the characteristic parameteracquisition chart by using the determined scanning speed, and it ispossible to appropriately acquire the characteristic parameter for thedetermined scanning speed.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The frequency as the chart output condition shown in FIG. 49 representsa jetting frequency of the recording head. The jetting frequency isdetermined by the resolution in the main scanning direction in mostcases, the number of paths in the main scanning direction, and thescanning speed in the main scanning direction. The frequency shown inFIG. 49 represents a relative jetting frequency ratio using a jettingfrequency in Printing Mode A and Printing Mode B to which the lowresolution is applied.

As a jetting frequency in Printing Mode C and Printing Mode E to whichthe medium resolution is applied, a standard jetting frequency isapplied. As a jetting frequency in Printing Mode D and Printing Mode Fto which the high resolution is applied, a jetting frequency which isfour times as high as the standard jetting frequency is applied. As ajetting frequency in Printing Mode G to which the super-high resolutionis applied, a jetting frequency which is eight times as high as thestandard jetting frequency is applied.

It is assumed that the printing resolution in the main scanningdirection in Printing Mode C and Printing Mode E is 300 dots per inch.Since the number of paths in Printing Mode C and Printing Mode E is 2,as much dots as one raster may be arranged in the main scanningdirection with a printing resolution of 150 dots per inch by performingthe scanning of the recording head in the main scanning direction once.

Since the scanning speed in Printing Mode C and Printing Mode E is thestandard speed, the standard jetting frequency is applied in PrintingMode C and Printing Mode E, similarly to Printing Mode A and PrintingMode B in which as much dots as one raster are arranged in the mainscanning direction with the printing resolution of 150 dots per inch inthe main scanning direction at the standard scanning speed.

It is assumed that the printing resolution in the main scanningdirection in Printing Mode D and Printing Mode F to which the highresolution is applied is 600 dots per inch. Since the number of paths inPrinting Mode D and Printing Mode F is 2, as much dots as one raster maybe arranged in the main scanning direction with a printing resolution of300 dots per inch, that is, with a printing resolution which is twice ashigh as that in Printing Mode A and Printing Mode B by performing thescanning of the recording head in the main scanning direction once.

Since the scanning speed in Printing Mode D and Printing Mode F is twiceas high as the standard scanning speed, a jetting frequency which isfour times as high as the standard jetting frequency applied to PrintingA and Printing B in which the dots are arranged in the main scanningdirection with the printing resolution of 150 dots per inch at thestandard scanning speed is applied to a jetting frequency in PrintingMode D and Printing Mode F.

It is assumed that the printing resolution in the main scanningdirection in Printing Mode G to which the super-high resolution isapplied is 1200 dots per inch. Since the number of paths in PrintingMode G is 4, as much dots as one raster may be arranged in the mainscanning direction with a printing resolution of 300 dots per inch, thatis, with a printing resolution which is twice as high as that ofPrinting Mode A and Printing Mode B by performing the scanning of therecording head in the main scanning direction once.

Since the scanning speed in Printing Mode G is four times as high as thestandard scanning speed, a jetting frequency which is eight times ashigh as the standard jetting frequency applied to Printing Mode A andPrinting B in which the dots are arranged in the main scanning directionwith the printing resolution of 150 dots per inch at the standardscanning speed is applied to a jetting frequency in Printing Mode G.

If Printing Mode A, Printing Mode B, Printing Mode C and Printing Mode Eare selected, the characteristic parameter acquisition chart is outputat the standard jetting frequency. If Printing Mode D and Printing ModeF are selected, the characteristic parameter acquisition chart is outputat a jetting frequency which is four times as high as the standardjetting frequency. If Printing Mode G is selected, the characteristicparameter acquisition chart is output at a jetting frequency which iseight times as high as the standard jetting frequency.

If the jetting frequency is different, the characteristic parameterssuch as the dot density, the dot diameter, the dot shape and the dotforming position shift for each printing element, and the position shiftfor each droplet kind are influenced.

In a case where the frequency shown in FIG. 49 is determined by theprinting mode, it is possible to output the characteristic parameteracquisition chart by using the determined jetting frequency, and it ispossible to appropriately acquire the characteristic parameter for thedetermined jetting frequency.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The unidirectional scanning or the bidirectional scanning as the chartoutput condition shown in FIG. 49 represents whether or not to performthe printing for only a period of time during which the recording headscans in one direction of the main scanning direction, and whether ornot to perform the printing for both a period of time during which therecording head scans in the one direction of the main scanning directionand a period of time during which the recording head scans in the otherdirection of the main scanning direction.

In FIG. 49, uni represents the unidirectional scanning, and birepresents the bidirectional scanning. In the unidirectional scanning, aprinting speed is slower than that in the bidirectional scanning, butsince the position shift caused by the bidirectional scanning, which mayoccur when the bidirectional scanning is performed, does not occur, itis possible to perform the printing with high quality. In the presentembodiment, the unidirectional scanning is applied to Printing Mode G towhich the super-high resolution is applied, and the bidirectionalscanning is applied to Printing Mode A to Printing Mode F. The printingspeed mentioned herein is an index indicating a printing time per unitsheet of the printing medium.

If Printing Mode A to Printing Mode F are selected, the characteristicparameter acquisition chart is output both in the outward path and theinward path through the bidirectional scanning. If Printing Mode G isselected, the characteristic parameter acquisition chart is output inonly the outward path through the unidirectional scanning.

In a case where the scanning type indicating whether or not to performthe unidirectional scanning or the bidirectional scanning shown in FIG.49 is determined by the printing mode, it is possible to output thecharacteristic parameter acquisition chart by using the determinedscanning type, and it is possible to appropriately acquire thecharacteristic parameter for the determined scanning type.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The nozzle as the chart output condition shown in FIG. 49 represents ausage nozzle range. As an aspect of the usage nozzle range, there is thenumber of nozzle to be used. The usage nozzle range is determined by thenumber of paths in most cases, and a pitch between nozzles. In thepresent embodiment, some of the nozzles are used in Printing Mode G towhich the super resolution is applied, and all the nozzles are used inPrinting Mode A to Printing Mode F.

As an example of the number of nozzles of some of the nozzles applied toPrinting Mode G, the number of nozzles of some of the nozzles is 44 in acase where the number of nozzles provided at the recording head is 50.

If Printing Mode A to Printing Mode F are selected, the characteristicparameter acquisition chart is output using all the nozzles. If PrintingMode G is selected, the characteristic parameter acquisition chart isoutput using some of the nozzles.

In a case where the nozzles shown in FIG. 49 is determined by theprinting mode, it is possible to output the characteristic parameteracquisition chart by using the determined nozzles, and it is possible toappropriately acquire the characteristic parameter for the determinednozzles.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

The transport amount as the chart output condition shown in FIG. 49represents the transport amount of the printing medium which is adistance at which the printing medium is moved by transporting theprinting medium in the sub scanning direction once. The transport amountis determined by the resolution in the sub scanning direction in mostcases, the pitch between the nozzles in the sub scanning direction, thenumber of nozzles and the number of paths in the main scanningdirection. In the present embodiment, the distance at which the printingmedium is moved by transporting the printing medium in the sub scanningdirection once is represented as a multiple of a unit movement amountusing an inverse number of a substantial resolution in the sub scanningdirection as the unit movement amount. The substantial resolution in thesub scanning direction is calculated by dividing the pitch between thenozzles by the number of paths in the sub scanning direction.

As for the resolution in the sub scanning direction in each printingmode, the low resolution is applied to Printing Mode A and Printing ModeB, and the medium resolution is applied to Printing Mode C and PrintingMode E. The high resolution is applied to Printing Mode D and PrintingMode F, and the super-high resolution is applied to Printing Mode G.

As an example of the resolution in the sub scanning direction, there isan aspect in which the low resolution is 150 dots per inch, the mediumresolution is 300 dots per inch, the high resolution is 600 dots perinch, and the super-high resolution is 1200 dots per inch. The lowresolution in the main scanning direction and the low resolution in thesub scanning direction may be the same resolution, or may be differentresolutions. The medium resolution in the main scanning direction andthe medium resolution in the sub scanning direction may be the sameresolution, or may be different resolution. The high resolution in themain scanning direction and the high resolution in the sub scanningdirection may be the same resolution, or may be different resolution.The super-high resolution in the main scanning direction and thesuper-high resolution in the sub scanning direction may be the sameresolution, or may be different resolution.

As the transport amount shown in FIG. 49, a transport amount which is 50times as large as the unit movement amount is applied to Printing Mode Aand Printing Mode B to which the low resolution in the sub scanningdirection is applied, a transport amount which is 25 times as large asthe unit movement amount is applied to Printing Mode C and Printing ModeE to which the medium resolution is applied, a transport amount which is25 times as large as the unit movement amount is also applied toPrinting Mode D and Printing Mode F to which the high resolution isapplied, and a transport amount which is 11 times as large as the unitmovement amount is applied to Printing Mode G to which the super-highresolution is applied.

If Printing Mode A and Printing Mode B are selected, the characteristicparameter acquisition chart is output by applying the transport amountwhich is 50 times as large as the unit movement amount. If Printing ModeC, Printing Mode D, Printing Mode E and Printing Mode F are selected,the characteristic parameter acquisition chart is output by applying thetransport amount which is 25 times as large as the unit movement amount.If Printing Mode G is selected, the characteristic parameter acquisitionchart is output by applying the transport amount which is 11 times aslarge as the unit movement amount.

If the transport amount is different, the characteristic parameter suchas the paper transport error is influenced.

In a case where the transport amount shown in FIG. 49 is determined bythe printing mode, it is possible to output the characteristic parameteracquisition chart by using the determined transport amount, and it ispossible to appropriately acquire the characteristic parameter for thedetermined transport amount.

Since the characteristic parameter acquisition chart can be outputwithout using the unused ink kind, in a case where the content of thecharacteristic parameter acquisition chart is reduced, it is possible toreduce the usage amount of ink in the outputting of the characteristicparameter acquisition chart, it is possible to reduce the usage amountof printing medium, and it is possible to reduce the processing timeuntil the characteristic parameter is acquired from the outputting ofthe characteristic parameter acquisition chart.

Among the setting items shown in FIG. 49, the items of the ink kind, thedroplet kind and the nozzle are classified as the chart items related tothe contents of the characteristic parameter acquisition chart. Thenumber of paths, the scanning speed, the frequency, the unidirectionalscanning or the bidirectional scanning, and the transport amount areclassified as the scanning conditions related to the operations of theprinting device. The ink kind corresponds to the kind of liquid used tooutput the characteristic parameter acquisition chart. The droplet kindcorresponds to the kind of liquid droplet of the liquid used to outputthe characteristic parameter acquisition chart. The nozzle correspondsto the printing element used to output the characteristic parameteracquisition chart. The number of paths is an aspect of the scanning typeapplied to the outputting of the characteristic parameter acquisitionchart. The scanning speed corresponds to the scanning speed applied tothe outputting of the characteristic parameter acquisition chart. Thefrequency corresponds to the jetting frequency applied to the outputtingof the characteristic parameter acquisition chart. The unidirectionalscanning or the bidirectional scanning is an aspect of the scanning typeapplied to the outputting of the characteristic parameter acquisitionchart. The transport amount corresponds to the transport amount of theprinting medium applied to the outputting of the characteristicparameter acquisition chart.

Although it has been described in the present embodiment that if theprinting mode is selected, both the chart items and the scanningconditions are set, the scanning conditions may be set depending on theselected printing mode in the printing system in which the chart itemsare fixed. In the printing system in which the scanning conditions arefixed, the chart items may be set depending on the selected printingmode. In other words, at least any one of the chart items or thescanning conditions may be set depending on the selected printing modeso as to correspond to the configuration of the printing system, and thecharacteristic parameter acquisition chart may be output depending onthe setting.

Although the plurality of chart items has been described in the presentembodiment that the plurality of chart items is collectively setdepending on the selected printing mode, at least any one chart item ofthe plurality of chart items may be set.

Although the plurality of scanning conditions has been described in thepresent embodiment that the plurality of scanning conditions iscollectively set depending on the selected printing mode, at least anyone scanning condition of the plurality of scanning conditions may beset. However, it is preferable that the plurality of scanning conditionsis collectively set depending on the selected printing mode.

Printing Mode A shown in FIG. 49 may be applied to a monochrome modeusing plain paper as the printing medium. Printing Mode B may be appliedto a four-color fast mode using the plain paper as the printing medium.Printing Mode C may be applied to a four-color standard mode using theplain paper as the printing medium. Printing Mode D may be applied to afour-color high-quality mode using the plain paper as the printingmedium.

Printing Mode E may be applied to a six-color standard mode using coatedpaper as the printing medium. Printing Mode F may be applied to asix-color high-quality mode using the coated paper as the printingmedium. Printing Mode G may be applied to a six-color super-high-qualitymode using the coated paper as the printing medium.

<Description of Method of Acquiring Characteristic Parameter>

FIG. 50 is a flowchart of a method of acquiring the characteristicparameter according to the seventh embodiment. In FIG. 50, the samesteps as those of FIG. 4 will be assigned the same reference numerals,and the description thereof will be appropriately omitted.

In a printing mode selection step S200 shown in FIG. 50, the printingmode is selected. The printing mode is selected in a printing modeselection unit 300 shown in FIG. 48.

If the printing mode is selected in the printing mode selection stepS200 shown in FIG. 50, the output condition of the characteristicparameter acquisition chart is set in a chart-output-condition settingstep S202. The output condition of the characteristic parameteracquisition chart is set by the chart-output-condition setting unit 302shown in FIG. 48.

If the chart output condition is set in the chart-output-conditionsetting step S202 shown in FIG. 50, the characteristic parameteracquisition chart is generated or selected and the generated or selectedcharacteristic parameter acquisition chart is output in a chart outputstep S204.

The characteristic parameter acquisition chart is generated by thecharacteristic-parameter-acquisition-chart generation unit 62 shown inFIG. 48. The characteristic-parameter-acquisition-chart generation unit62 of FIG. 48 may select the characteristic parameter acquisition chartstored in the characteristic-parameter-acquisition-chart storage unit304. The characteristic parameter acquisition chart is output by thedata output unit 66 shown in FIG. 48 and the printing device 24 shown inFIG. 1.

If the characteristic parameter acquisition chart is output in the chartoutput step S204 shown in FIG. 50, the output characteristic parameteracquisition chart is read in an image reading step S206. The imagereading step S206 is performed by the image reading device 26 shown inFIG. 1.

If the characteristic parameter acquisition chart is read in the imagereading step S206 shown in FIG. 50, the characteristic parameter isacquired by analyzing the read image of the characteristic parameteracquisition chart in a characteristic parameter acquisition step S208.

The characteristic parameter is acquired depending on the printing modethrough the printing mode selection step S200, thechart-output-condition setting step S202, the chart output step S204,the image reading step S206 and the characteristic parameter acquisitionstep S208 shown in FIG. 50.

That is, the printing mode selection step S200, thechart-output-condition setting step S202, the chart output step S204,the image reading step S206 and the characteristic parameter acquisitionstep S208 shown in FIG. 50 constitute the method of acquiring thecharacteristic parameter according to the present embodiment.

A halftone-processing-rule generation step S210, ahalftone-selection-chart output step S212 and a halftone selectionoperating step S214 shown in FIG. 50 are the same as thehalftone-processing-rule generation step S14, thehalftone-selection-chart output step S16 and the halftone selectionoperating step S18 the shown in FIG. 4, and the description thereof willbe omitted.

FIG. 51 is a flowchart of a method of acquiring the characteristicparameter according to a modification example of the seventh embodiment.In FIG. 51, the same steps as those of FIG. 50 will be assigned the samereference numerals, and the description thereof will be appropriatelyomitted.

In the flowchart shown in FIG. 50, it is not necessary to necessarilygenerate the halftone processing rule after the characteristicparameter. For example, as shown in FIG. 51, after the characteristicparameter may be acquired, the acquired characteristic parameter may beapplied for the error analysis of the printing system.

That is, in the method of acquiring the characteristic parameter shownin FIG. 51, an error message display step S220 is performed after thecharacteristic parameter acquisition step S208. The error messagedisplay step S220 compares the existing characteristic parameteracquired in the past with the new characteristic parameter newlyacquired, extracts the characteristic parameter in a case where thecharacteristic parameter having a difference which exceeds apredetermined specified value is present between the existingcharacteristic parameter and the new characteristic parameter, displaysthe extracted characteristic parameter, and displays an error message.An error occurrence determination unit that determines whether or not anerror occurs in the image processing device 20B shown in FIG. 48 isprovided. The error occurrence determination unit functions as erroroccurrence determination means.

The error message may be displayed on the display device 32 shown inFIG. 48. The display device 32 shown in FIG. 48 may function as errormessage display means for displaying the error message.

When the image defect such as unevenness or streak occurs, the user mayperform the error analysis according to the flowchart shown in FIG. 51,or the error analysis may be regularly performed irrespective of whetheror not the image defect occurs. As an example in which the erroranalysis is regularly performed, there are a point of time when theprint job is started, or a point of time when the printing system isstarted. The error analysis may be irregularly performed based on thedetermination of the user.

The specified value may be a constant value, or may be updated when thenew characteristic parameter is acquired. The specified value may bedetermined based on a variation in characteristic parameter calculatedaccording to the acquisition of the characteristic parameter overmultiple times. As an example in which the variation is used as thespecified value, there is an aspect in which ±σ or ±2σ shown in FIG. 31is used as the specified value. The aspect shown in FIG. 51 may becombined with the aspect shown in FIG. 50.

<Description of Characteristic Parameter>

As an example of the characteristic parameter applied to the printingsystem according to the present embodiment, there is a dot density, adot diameter, a dot shape, a dot forming position shift and non-jettingfor each printing element, and a position shift for each droplet kind.The specified value of the dot density, the dot diameter or the dotshape of FIG. 40 may be an absolute value, or may be determined as aratio with respect to the existing dot density, dot diameter and dotshape.

The specified value shown in FIG. 51 may be determined with a rangeincluding the plurality of nozzles such as a nozzle array or a pluralityof neighboring nozzles as a target.

Since change characteristics are different for each droplet kind, thespecified value shown in FIG. 40 may be determined for each dropletkind.

As for the non-jetting, in the error message display step S220 of FIG.51, the error message may be displayed in a case where the non-jettingoccurs in one nozzle, or the error message may be displayed in a casewhere the non-jetting occurs in the plurality of nozzles that exceeds apredetermined specified value in an arbitrary range.

As the characteristic parameter specific to the serial scanning, thereare a bidirectional scanning position shift of scanning, a bidirectionalprinting position shift of scanning for each droplet kind, a headvibration error according to carriage movement, and a paper transporterror. The bidirectional scanning position shift of scanning correspondsto a bidirectional printing position shift. The bidirectional printingposition shift of scanning for each droplet kind corresponds to abidirectional scanning position shift for each droplet kind. The headvibration error according to the carriage movement corresponds to avibration error of the image forming unit. The paper transport errorcorresponds to a transport error of the printing medium.

As the specified value in a case where the head vibration erroraccording to the carriage movement is the characteristic parameter, anindex indicating a difference between the existing head vibration erroraccording to the carriage movement and the new head vibration error maybe applied. As the index indicating the difference between the existinghead vibration error according to the carriage movement and the new headvibration error, the summation of the absolute values of the differencesbetween the existing position shift amounts in the main scanningdirection and the new position shift amounts in the main scanningdirection in the shift amount Δx(n) in the main scanning direction withrespect to the pixel position n shown in FIG. 25A or the summation ofsquares of the differences may be applied. The difference between theexisting position shift amount in the main scanning direction and thenew position shift amount in the main scanning direction may becalculated by subtracting the existing position shift amount in the mainscanning direction from the new position shift amount in the mainscanning direction.

As the index indicating the difference between the existing headvibration error according to the carriage movement and the new headvibration error according to the carriage movement, the summation orsummation of squares of ratios between the existing position shiftamounts in the main scanning direction and the new position shiftamounts in the main scanning direction in the shift amount Δx(n) in themain scanning direction with respect to the pixel position n shown inFIG. 25A may be applied. The ratio between the existing position shiftamount in the main scanning direction and the new position shift amountin the main scanning direction may be calculated by dividing the newposition shift amount in the main scanning direction by the existingposition shift amount in the main scanning direction.

The shift amount Δy(n) in the sub scanning direction with respect to thepixel position n shown in FIG. 25B may be applied instead of or togetherwith the shift amount Δx(n) in the main scanning direction with respectto the pixel position n.

As the specified value in a case where the head vibration erroraccording to the carriage movement, the index indicating similarity maybe applied. As the similarity, a correlation coefficient may be applied.The specified value in a case where the head vibration error accordingto the carriage movement is the characteristic parameter may bedetermined based on the magnitude of the head vibration error accordingto the carriage movement. As the magnitude of the head vibration erroraccording to the carriage movement, a standard deviation or a varianceof the magnitude of the head vibration error according to the carriagemovement may be applied. The head vibration error according to thecarriage movement corresponds to the head vibration error.

As the characteristic parameter specific to the single path type, thereis the vibration error of the head module (denoted by reference numeral220-j (=1, 2, . . . , and Nm) in FIG. 28).

As the specified value shown in FIG. 40 in a case where the head modulevibration error in the single path type is the characteristic parameter,the index indicating the difference between the existing head modulevibration error and the new head module vibration error may be applied.As the index indicating the difference between the existing head modulevibration error and the new head module vibration error, the summationof the absolute values of the differences between the existing positionshift amounts in the main scanning direction and the new position shiftamounts in the main scanning direction in the position shift amounts(dot position shift amounts) of the main scanning direction (denoted byreference numeral x) with respect to the position in the paper transportdirection (sub scanning direction, denoted by reference numeral y) shownin FIG. 28 or the summation of squares of the differences may beapplied.

The difference between the existing position shift amount in the mainscanning direction and the new position shift amount in the mainscanning direction may be calculated by subtracting the existingposition shift amount in the main scanning direction from the newposition shift amount in the main scanning direction.

As the index indicating the difference between the existing head modulevibration error and the new head module vibration error, the summationor summation of squares of the ratios between the existing positionshift amount in the main scanning direction and the new position shiftamount in the main scanning direction in the position shift amounts (dotposition shift amounts) in the main scanning direction (denoted byreference numeral x) with respect to the position in the paper transportdirection (sub scanning direction, denoted by reference numeral y) shownin FIG. 28 may be applied.

The ratio between the existing position shift amount in the mainscanning direction and the new position shift amount in the mainscanning direction may be calculated by dividing the new position shiftamount in the main scanning direction by the existing position shiftamount in the main scanning direction.

As the specified value in a case where the head module vibration errorin the single path type is the characteristic parameter, the indexindicating the similarity between the existing head module vibrationerror and the new head module vibration error may be applied. As theindex indicating the similarity between the existing head modulevibration error and the new head module vibration error, a correlationcoefficient may be applied. The head module vibration error correspondsto a head module vibration error in a head formed using the plurality ofhead modules.

The specified value in a case where the head module vibration error isthe characteristic parameter may be determined based on the magnitude ofthe head module vibration error. As the magnitude of the head modulevibration error, a standard deviation or a variance of the magnitude ofthe head module vibration error may be applied.

According to the printing system having the above-describedconfiguration and the method of acquiring the characteristic parameter,it is possible to appropriately comprehend the characteristic parametersindicating the characteristics of the printing system for the respectiveprinting modes.

Since the characteristic parameter acquisition chart is optimized, in acase where the characteristic parameter acquisition chart is reduced, itis possible to reduce the processing time until the characteristicparameter is acquired after the characteristic parameter acquisitionchart is output. It is possible to reduce the usage amount of used inkand the usage amount of the printing medium until the characteristicparameter is acquired after the characteristic parameter acquisitionchart is output.

In the printing system and the method of acquiring the characteristicparameter described in the present embodiment, the plurality of printingmodes may be selected, the chart output conditions may be respectivelyset to the plurality of selected printing modes, the characteristicparameter acquisition charts may be respectively output for theplurality of selected printing modes, and the characteristic parametermay be acquired for the plurality of selected printing modes. Theplurality of printing modes may be all the printing modes, or may besome of the printing modes.

According to such as aspect, in a case where the plurality of printingmodes is changed in one job, it is possible to acquire the optimumcharacteristic parameters appropriate for the plurality of printingmodes for the plurality of printing modes by outputting thecharacteristic parameter acquisition charts once.

Eighth Embodiment: Another Example of Method of Generating HalftoneProcessing Rule

[Example in User Input Characteristic Parameter]

FIG. 52 is a flowchart showing another example of the method ofgenerating the halftone processing rule shown in FIG. 4. The flowchartshown in FIG. 52 includes a process (step S13) of allowing the user toinput the characteristic parameters related to the characteristics ofthe printing system instead of the process (step S10) of outputting thecharacteristic parameter acquisition chart, the process (step S11) ofreading the characteristic parameter acquisition chart output in stepS10 and the process (step S12) of acquiring the characteristicparameters related to the characteristics of the printing system in theflowchart shown in FIG. 4.

As means for allowing the user to input the characteristic parametersrelated to the characteristics of the printing system, the displaydevice 32 and the input device 34 shown in FIGS. 2 and 3 may be applied.That is, the user can input the characteristic parameters related to thecharacteristics of the printing system by using the input device 34while seeing the content displayed on the screen of the display device32 shown in FIGS. 2 and 3.

As the characteristic parameters related to the characteristics of theprinting system, in the ink jet printing system, there are a dropletkind and a jetting order in addition to the resolution, the number ofnozzles and the ink kind already described. As the characteristicparameter specific to the serial scan type, there is bidirectionalprinting or unidirectional printing. These characteristic parameters arecharacteristic parameters related to the specifications of the printingsystem.

As common characteristic parameters to the plurality of printingelements, there are an average dot forming position shift and an averageposition shift for each droplet kind, in addition to the average dotdensity, the dot diameter, the average dot shape and the landinginterference already described.

As the characteristic parameter of an individual printing element, thereis a position shift for each droplet kind in addition to the dotdensity, the dot diameter, the dot shape, the dot forming position shiftand the non-jetting for each printing element.

As the characteristic parameter specific to the serial scanning, thereare a position shift between the outward path and the inward path in thebidirectional printing, a position shift between the outward path andthe inward path in the bidirectional printing for each droplet kind, anda paper transport error.

As the characteristic parameter specific to the single path type, thereis a recording head attachment error.

As another characteristic parameter which does not belong to theabove-described classifications, there is an error caused by thevibration of the recording head.

In a case where the user inputs an appropriate value for thecharacteristic parameter of the individual printing element among thecharacteristic parameters, an operation load becomes high. However, asfor the non-jetting, since the user may input such that the non-jettingoccurs in a limited number of printing elements, the above-describedconfiguration is applied to the inputting of the characteristicparameter of the individual printing element other than the non-jetting.

When the user inputs the characteristic parameter of the individualprinting element, the image processing device 20 described in thepresent embodiment is configured to input an average value of theplurality of printing elements or an average equivalent value which is avalue equivalent to the average value. The image processing device isconfigured to input a deviation from the average value or the averageequivalent value. As for the characteristic parameters other than thecharacteristic parameter of the individual printing element, the imageprocessing device may be configured to input an average value or anaverage equivalent value and a deviation from the average value or theaverage equivalent value for the characteristic parameters for which theaverage value or the average equivalent value and the deviation from theaverage value or the average equivalent value can be input.

The average equivalent value is a value equivalent to the average valuecapable of being substantially treated as an average value. As anexample of the average equivalent value, there are a center value and arepresentative value (representative value capable of being treated tobe equivalent to the average value).

When a target range of the average value or the average equivalent valueand the deviation from the average value or the average equivalent valueare defined, all the printing elements which are provided as theplurality of printing elements at the recording head may be used astargets, or some printing elements of the printing elements provided atthe recording head may be used as targets.

As an example of some printing elements of the printing elementsprovided at the recording head, there are printing elements for the headmodules 220-j shown in FIG. 28. That is, an average value of thecharacteristic parameters or an average equivalent value and a deviationfrom the average value or the average equivalent value may be input foreach of the head modules 220-j shown in FIG. 28.

Some printing elements of the printing elements provided at therecording head may be appropriately set so as to correspond to theaspect in which the halftone processing rule is generated.

For the dot density, the dot diameter, the dot forming position shiftand the position shift for each droplet kind, an average value or anaverage equivalent value and a deviation from the average value or theaverage equivalent value of values (a density value, a diameter value, adistance of the dot forming position shift, and a distance of theposition shift) indicating the degrees or quantities thereof in theplurality of printing elements.

A value acquired by digitizing the degree of collapse of the dot shapefrom an ideal dot shape (perfect circle) may be used an input value ofthe dot shape, and an average value of the plurality of printingelements or an average equivalent value and a deviation (an averagevalue of values indicating the degrees of collapse of the respectivedots formed using the plurality of printing elements or an averageequivalent value, and a deviation from the average value or the averageequivalent value) from the average value or the average equivalent valuemay be input as an average value of the dot shapes or an averageequivalent value and a deviation from the average value or the averageequivalent value.

For example, a radius from the origin of the dot to the circumference isa/2 in all directions of 360 degrees in a case where the dot has anideal dot shape (perfect circle) of which the dot diameter is a, anddifference radiuses are varied by a radius different from a/2 in therespective directions of 360 degrees in a case where the dot has thecollapsed dot shape. Accordingly, the standard deviation of variationsin ratios of the radiuses in the respective directions of 360 degrees toa/2 may be used as an index indicating the degree of collapse of thedot, and may be input as the average value of the plurality of printingelements or the average equivalent value and the deviation from theaverage value or the average equivalent value.

The process (step S13) of causing the user to input characteristicparameters related to the characteristics of the printing system, whichis shown in FIG. 52 functions as an information input process of causingthe user to input the characteristic parameter. The information inputprocess includes an average input process of causing the user to inputan average value of the characteristic parameters or an averageequivalent value and a deviation input process of causing the user toinput a deviation from the average value of the characteristicparameters or the average equivalent value.

FIG. 53 is an explanatory diagram showing an example of an input screenused in the input process of the flowchart shown in FIG. 52. An inputscreen 32A shown in FIG. 53 is displayed on the display device 32 shownin FIG. 3.

The input screen 32A shown in FIG. 53 includes an input field 33A of theaverage value (or average equivalent value) of the dot density, an inputfield 33B of the deviation of the dot density, an input field 33C of theaverage (or average equivalent value) of the dot diameter, an inputfield 33D of the deviation of the dot diameter, an input field 33E ofthe average value (or average equivalent value) of the dot shape, aninput field 33F of the deviation of the dot shape, an input field 33G ofthe average value (or average equivalent value) of the dot formingposition shift, an input field 33H of the deviation of the dot formingposition shift, an input field 33K of the average value (or averageequivalent value) of the position shift for each droplet kind, an inputfiled 33L of the position shift for each droplet kind, an input field33M of the average value (or average equivalent value) of the recordinghead vibration (head vibration), and an input field 33N of the deviationof the recording head.

However, it is not necessary to input all the items, and it is possibleto select the input target item depending on the characteristics of theprinting system. That is, among of the items shown in FIG. 53, at leasta group of average values or average equivalent values and deviationsfrom the average value or the average equivalent value may be input.

The inputting of the average value or the average equivalent valuecorresponds to the determination of Value A (average value) of thecharacteristic error of the graph showing the relationship between thesystem error distribution and the level of the random system error shownin FIG. 31. That is, as the average equivalent value, Value A of thecharacteristic error shown in FIG. 31 may be adopted.

The inputting of the deviation corresponds to the determination of ±σ orσ±2 which is the standard deviation of the graph showing therelationship between system error distribution and the level of therandom system error shown in FIG. 31.

The vibration error of the recording head is not the characteristicparameter of the individual printing element, but since the vibrationerror of the recording head has high reproducibility, the vibrationerror of the recording head can be treated as the same error as thecharacteristic error. The image processing device described in thepresent embodiment is configured to input the average value (or theaverage equivalent value) of the recording head positions, and thedeviation of the recording head positions as the recording headvibration error.

FIG. 54 is an explanatory diagram showing another example of the dotshape item on the input screen shown in FIG. 53. In the ink jet typeprinting system, the shape of the dot generated from one liquid dropletmay be an elliptical shape, or the one liquid droplet may be dividedinto a plurality of liquid droplets (a main droplet and sub droplets aregenerated).

The input screen 32B of the dot shape shown in FIG. 54 includes an inputfield 35A of an average value (or average equivalent value) of thelengths in the main scanning direction, an input field 35B of adeviation of the lengths in the main scanning direction, an input field35C of an average value (or average equivalent value) of the lengths inthe sub scanning direction, and an input field 35D of a deviation of thelengths in the sub scanning direction so as to correspond to a casewhere the shape of the dot has the elliptical shape.

An input field 35E of an average value (or average equivalent value) ofthe distances between the main droplet and the sub droplet, and an inputfield 35F of a deviation of the distances between the main droplet andthe sub droplets so as to correspond to a case where the liquid dropletjetted as one liquid droplet is divided into the plurality of liquiddroplets.

As the length in the main scanning direction on the input screen 32B ofthe dot shape shown in FIG. 54, the length (dot diameter) of the dot inthe main scanning direction may be applied. As the length in the subscanning direction, the length (dot diameter) of the dot in the subscanning direction may be applied.

The distance between the main droplet and the sub droplet may be adistance between a center of the main droplet and a center of the subdroplet, or may be the shortest distance between the outer circumferenceof the main droplet and the circumference of the sub droplet. Althoughnot shown in FIG. 54, the input fields of the average value (or averageequivalent value) and the deviation of the lengths in the main scanningdirection and the lengths of the sub scanning direction may be providedfor the main droplet and the sub droplet. In a case where the inputscreen 32B of the dot shape is provided, the input field of the dotdiameter is omitted.

By doing this, in a case where the user inputs the characteristicparameters related to the characteristics of the printing system, sincethe average value of the characteristic parameters of the plurality ofprinting elements or an average equivalent value and a deviation fromthe average value or the average equivalent value are input, thecharacteristic parameter for the individual printing element isprevented from being input, and an excessive load is prevented frombeing given to the inputting of the characteristic parameter.

Although it has been described in the present embodiment that the inputdevice 34 and the input screens 32A and 32B are individual components,the input device 34 and the input screens 32A and 32B may be integrallyformed using a touch panel type display device.

As an aspect of the information input means, a configuration in whichinput screens displayed on the input device 34 and the display device 32shown in FIG. 2 are included may be adopted. The input device 34 shownin FIG. 2, the input screen 32A shown in FIG. 53 and the input screen32B shown in FIG. 54 function as average value input means for causingthe user to input the average value of the parameters of the pluralityof printing elements provided in the printing system or the averageequivalent value, or the average value of the errors due to thevibration of the recording head provided in the printing system or theaverage equivalent value.

The input device 34 shown in FIG. 2, the input screen 32A shown in FIG.38 and the input screen 32B shown in FIG. 54 function as deviation inputmeans for inputting the deviation from the average value or the averageequivalent value. That is, an aspect of the information input means, anaspect in which the average value input means and the deviation inputmeans are included may be adopted.

Ninth Embodiment: Example of Halftone Processing Rule Generation Due toLanding Interference Simulation

FIG. 55 is a flowchart of the aspect in which the influence of thelanding interference when the simulation image shown in FIG. 11 isgenerated is reflected. The simulation image generation to be describedbelow is to generate the simulation image in which the influence of thelanding interference is reflected, is applied to the serial scan typeink jet printing system shown in FIG. 6, and is applied to an operationmode in which the drawing is completed through multipath. The printingtype in the serial scan type ink jet printing device functions as theprinting system that executes the serial scan type printing.

In the present embodiment, the influence of the landing interference issimulated in consideration of an inter-dot jetting time difference aswell as the inter-dot distance. In the present embodiment, inter-colorlanding interference and a difference in landing interference accordingto the liquid kind are simulated.

That is, the image processing device applied to the printing systemdescribed in the present embodiment generates the simulation image inwhich the influence of the landing interference is reflected and whichincludes a plurality of colors, the simulation image in which theinter-color landing interference is reflected and which includes dotscorresponding to the plurality of droplet kinds, the simulation image inwhich the influence of the landing interference caused by the dropletkind is reflected, the simulation image in which the influence of thelanding interference caused by the inter-dot distance is reflected andthe simulation image in which the influence of the landing interferencecaused by the jetting time difference is reflected.

The simulation image generated shown in the flowchart of FIG. 55 isperformed by repeating step S26A (dot arrangement process) for eachscanning path and step S26B (dot rearranging process) for each scanningpath.

In the dot arrangement process shown in step S26A, the characteristicparameter is reflected on the dots of the respective pixels of therespective colors jetted along a k-th path, and the dots are arranged onthe simulation image.

In the dot arrangement step S26A, if the dots are arranged on thesimulation image, the process proceeds to the dot rearranging step S26B.In the dot rearranging step S26B, at least any one of the dot movementdue to the landing interference with the already arranged surroundingdots and the surrounding dots of another color jetted along the samepath, a density change of the dots or a shape change of the dots isreflected on the dots of the respective pixels of the respective colorsjetted along the k-th path, and the dots are rearranged on thesimulation image. The already arranged dots are dots arranged from afirst scanning path to a (k−1)-th path.

The surrounding dots are dots in which the landing interference with thedots (given dots) as rearranging targets may occur, and are counterpartdots of the white dots constituting the pixels different from the givendots.

The given dot is a target dot (rearranging target dot) on which theinfluence of the landing interference is reflected, and refers to atarget dot on which the determination of whether or not the influence ofthe landing interference is influenced is performed. The surroundingrefers to a range in which the counterpart dots (surrounding dots) arepresent when the determination of whether or not the given dots areinfluenced by the influence of the landing interference is performed.

In a case where the landing interference occurs, one or more surroundingdots are present for one given dot. The dot movement, the density changeof the dots or the shape change of the dots due to the influence of thelanding interference are simulated based on the inter-dot distance andthe jetting time difference.

In the dot rearranging step S26B, if the dots are rearranged on thesimulation image along the k-th path and the dot arrangement on whichthe influence of the landing interference is reflected is determined,the process proceeds to the next scanning path ((k+1)-th path).

If the dot arrangement step S26A and the dot rearranging step S26B areperformed on the (k+1)-th path and the dot arrangement on which theinfluence of the landing interference of the (k+1)-th path is reflectedis determined, the process proceeds to the next scanning path ((k+2)-thpath). By doing this, the dot arrangement of the simulation image inwhich the influence of the landing interference is determined along allthe scanning paths.

FIG. 56 is a conceptual diagram in which the jetting order of thedrawing mode in which the drawing is performed along 8 scanning paths isdenoted by a path number. The number of scanning paths and the jettingorder shown in FIG. 56 are acquired by adding one row is added in a rowdirection and one column is added in a column to the number of scanningpaths and the jetting order shown in FIGS. 12 and 13. The number ofscanning paths and the jetting order shown in FIG. 56 are substantiallythe same as those of the number of scanning paths and the jetting ordershown in FIGS. 12 and 13, and the description thereof is omitted.

A dot patch in FIG. 56 represents a difference in droplet kind. That is,a light dot patch represents that a small droplet (small dot) is jetted.A dark dot patch represents that a medium droplet (medium dot) isjetted.

FIG. 57 is a conceptual diagram of the simulation image showing thearrangement of the dots jetted along the first path in the generation ofthe simulation image. In the following description, a simulation imageusing two colors of magenta and black will be described. It is assumedthat the positions where magenta dots are jetted and the positions whereblack dots are jetted in the same path are shifted in the sub scanningdirection by two pixels. The same is true of FIGS. 58A, 58B, 59A and59B.

In the simulation image generation (dot arrangement and dotrearrangement) to be described below, the dot density for each dropletkind, the dot diameter for each droplet kind and the dot shape (circle)for each droplet kind as the characteristic parameters are reflected onthe dots jetted along the respective scanning paths. Meanwhile, theerror such as the dot forming position shift is not reflected. As theinfluence of the landing interference, the dot movement is reflected.The dot movement is the concept including the movement distance and themovement direction.

In FIG. 57, alphabets of the reference numeral assigned to the dotrepresent the droplet kind and color of the dot. mm represent magentaand medium droplet. ms represent magenta and small droplet. bm representblack and medium droplet. bs represent black and small droplet. In FIG.57, among numbers of the reference numerals assigned to the dot, thetens digit represents the number of scanning paths, and the ones digitrepresents a serial number assigned to the dot.

For example, dot mm12 represents the magenta, medium and second dotjetted along the first path. The same is true of FIGS. 58A, 58B, 59A and59B.

As shown in FIG. 57, the magenta dots ms11, mm12, ms13 and ms14 and theblack dots bs11 and bm12 which are jetted along the first path are notin contact with each other, and the landing interference does not occurin these dots. In the simulation image generation described in thepresent embodiment, in a case where the inter-dot distance and the sumof radiuses of two dots are the same value, these dots are treated asbeing not in contact with each other. That is, the contact in thesimulation image generation described in the present embodiment refersto a state in which there is a region where two dots overlap each other.The dot arrangement shown in FIG. 57 refers to dot arrangement in whichthe dots are arranged in the dot arrangement step S26A shown in FIG. 55.

FIG. 58A is a conceptual diagram of the simulation image showing thearrangement of the dots jetted up to the second path in the generationof the simulation image. FIG. 58B is a conceptual diagram of thesimulation image showing the dot arrangement in which the dots arerearranged by reflecting the influence of the landing interference.

As shown in FIG. 58A, the magenta dots ms21 and mm22 and the black dotsbm21 and bs22 are jetted along the second path. Since the magenta dotms21 jetted along the second path is in contact with the magenta dotmm12 jetted along the first path, the landing interference occursbetween these dots. The magenta dot ms21 jetted along the second path ismoved toward the magenta dot mm12 jetted along the first path due to theinfluence of the landing interference.

Similarly, since the black dot bs22 jetted along the second path is incontact with the black dot bm12 jetted along the first path, the landinginterference occurs between these dots. The black dot bs22 jetted alongthe second path is moved toward the black dot bm12 jetted along thefirst path due to the influence of the landing interference. A thickarrow line shown in FIG. 58A represents the movement direction of thedot due to the influence of the landing interference.

The dot arrangement shown in FIG. 58B is dot arrangement in which thedots are rearranged by reflecting the influence of the landinginterference. The magenta dot ms21 of FIG. 58B is rearranged so as to beshifted toward the magenta dot mm12 by reflecting the influence of thelanding interference. Similarly, the magenta dot bs22 is rearranged soas to be shifted toward the black dot bm12 by reflecting the influenceof the landing interference.

FIG. 59A is a conceptual diagram of the simulation image showing thearrangement of the dots jetted along the third path in the generation ofthe simulation image. FIG. 59B is a conceptual diagram of the simulationimage showing the arrangement of the dots in which the dots arerearranged by reflecting the influence of the landing interference.

As shown in FIG. 59A, the magenta dots mm31 and mm32 and the black dotsbs31, bs32, bm33 and bm34 are jetted along the third path. The dotsjetted along the third path are arranged on the simulation image inwhich the dots are rearranged in the jetting along the second path shownin FIG. 58B.

Since the black dot bs32 jetted along the third path is in contact withthe black dot bm21 jetted along the second path, the landinginterference occurs between these dots. The black dot bs32 jetted alongthe third path is moved toward the black dot bm21 jetted along thesecond path due to the influence of the landing interference.

Similarly, since the black dot bm34 jetted along the third path is incontact with the magenta dot mm22 jetted along the second path, thelanding interference occurs between these dots. The black dot bm34jetted along the third path is moved toward the magenta dot mm22 jettedalong the second path due to the influence of the landing interference.A thick arrow line shown in FIG. 59A represents the movement directionof the dot due to the influence of the landing interference.

In the simulation image generation described in the present embodiment,it is assumed that in a case where there is a jetting time differencewhich is equal to or greater than two scanning paths between the dotsbeing in contact, the landing interference does not occur. That is, themagenta dot mm31 jetted along the third path is in contact with themagenta dot ms11 and the black dot bs11 jetted along the first path, butthe landing interference does not occur between the magenta dot mm31jetted along the third path and the magenta dot ms11 jetted along thefirst path and between the magenta dot mm31 jetted along the third pathand the black dot bs11 jetted along the first path.

Similarly, the black dot bm33 jetted along the third path is in contactwith the black dot bs11 and the magenta dot ms14 jetted along the firstpath, but the landing interference does not occur between the black dotbm33 jetted along the third path and the black dot bs11 jetted along thefirst path and between the black dot bm33 jetted along the third pathand the magenta dot ms14 jetted along the first path.

The dot movement due to the influence of the landing interference may beexpressed by a function f(c,p) using an inter-dot distance c and ajetting time difference p as the parameters. Since the landinginterference occurs between the surrounding dots in an arbitrarydirection, the inter-dot distance c may be considered as a vector usingthe center of the given dot as a start point and the center of thesurrounding dot as an end point. In a case where the inter-dot distancec is considered as the vector, the function f(c,p) is also treated avector having a direction indicated by the inter-dot distance c.

In the following description, it is assumed that the inter-dot distancec and the function f(c, p) indicating the dot movement are treated asthe vectors. It is assumed that the dot movement in the followingdescription is treated as the vector having the movement distance andthe movement direction.

FIG. 60 is an explanatory diagram of the inter-dot distance. Dot1 shownin FIG. 60 is a given dot. Dot2 and Dot3 are surrounding dots. Aninter-dot distance c1 between the given dot Dot1 and the surrounding dotDot2 is expressed as a vector using the center of the given dot Dot1 asa start point and the center of the surrounding dot Dot2 as an endpoint. Similarly, an inter-dot distance c2 between the given dot Dot1and the surrounding dot Dot3 is expressed as a vector using the centerof the given dot Dot1 as a start point and the center of the surroundingdot Dot3 as an end point.

In a case where the given dot is moved between the given dot and theplurality of surrounding dots due to the influence of the landinginterference, the movement of the given dot due to the influence of thelanding interference may be calculated as the summation of vectors ofthe movement due to the influence of the landing interference betweenthe given dot and the respective surrounding dots.

That is, if the landing interference occurs between the given dot Dot1and the surrounding dot Dot2 and the given dot and the surrounding dotDot3 shown in FIG. 60, the given dot Dot1 is moved in a direction fromthe center of the given dot Dot1 toward the center of the surroundingdot Dot2, and is moved in a direction from the center of the given dotDot1 toward the center of the surrounding dot Dot3. As a result, thegiven dot is moved toward a position where the movement is balanced inboth the directions.

A distance at which the given dot Dot1 is moved is determined by thebalance of surface tension between the given dot Dot1 and thesurrounding dot Dot2 and surface tension between the given dot Dot1 andthe surrounding dot Dot3. There is a tendency for the distance at whichthe given dot Dot1 is moved to become longer as the inter-dot distance(scalar quantity) becomes shorter, and there is a tendency for thedistance at which the given dot Dot1 is moved to become shorter as theinter-dot distance (scalar quantity) becomes longer.

In the example described in FIGS. 57 to 59B, the movement of each dotdue to the landing interference is expressed by Expression (11) toExpression (14).Σf _(bs_bs)(c,p)+Σf _(bs_bm)(c,p)+Σf _(bs_ms)(c,p)+Σf_(bs_mm)(c,p)  Expression (11)Σf _(bm_bs)(c,p)+Σf _(bm_bm)(c,p)+Σf _(bm_ms)(c,p)+Σf_(bm_mm)(c,p)  Expression (12)Σf _(ms_bs)(c,p)+Σf _(ms_bm)(c,p)+Σf _(ms_ms)(c,p)+Σf_(ms_mm)(c,p)  Expression (13)Σf _(mm_bs)(c,p)+Σf _(mm_bm)(c,p)+Σf _(mm_ms)(c,p)+Σf_(mm_mm)(c,p)  Expression (14)

Expression (11) corresponds to a case where the given dot is the blackdot and the small droplet. The movement of the dot bs22 shown in FIG.58A and the movement of the dot bs32 shown in FIG. 59A due to theinfluence of the landing interference are calculated using Expression(11).

Expression (12) corresponds to a case where the given dot is the blackdot and the medium droplet. The movement of the dot bm34 shown in FIG.59A due to the influence of the landing interference is calculated usingExpression (12). Expression (13) corresponds to a case where the givendot is the magenta dot and the small droplet. The movement of the dotms21 shown in FIG. 58A due to the influence of the landing interferenceis calculated using Expression (13). Expression (14) corresponds to acase where the given dot is the magenta dot and the medium droplet.

FIG. 61 is an explanatory diagram of the function f used in Expression(11) to Expression (14). In FIG. 61, the description of the parameters(the inter-dot distance c and the jetting time difference p) of thefunction f indicating the dot movement is omitted.

In Expression (11) to Expression (14), among suffixes assigned to thefunction f, suffixes on the left side of the underbar represent thecolor and droplet kind of the given dot in order from the left, andsuffixes on the right side of the underbar represent the color anddroplet kind of the surrounding dot in order from the left. For example,a first term of Expression (11) represents the summation of the movementof the given dots in a case where the given dot is the black dot, thesmall droplet and the surrounding dot is the black dot and the smalldroplet.

That is, the given dots are classified according to each color and eachdroplet kind, the surrounding dots are classified according to eachcolor and each droplet kind, and the movement of each dot due to theinfluence of the landing interference is calculated using a vectorsummation acquired by adding a vector function indicating the movementfor each classification of the surrounding dot to each classification ofthe given dot.

When the movement of the dot due to the influence of the landinginterference is calculated using Expression (11) to Expression (14), itmay be determined whether or not the landing interference occurs fromthe condition of the inter-dot distance c and the condition of thejetting time difference p, and the dot movement due to the influence ofthe landing interference may be calculated in only a case where thelanding interference occurs.

The surrounding dots which are not in contact with the given dots may beexcluded from the targets using the inter-dot distance c. In a casewhere the diameter of the white dot is DA and the diameter of thesurrounding dot is DB, the surrounding dots that satisfy the conditionof |c|≥(DA+DB)/2 may be excluded from the targets. That is, in a casewhere the inter-dot distance c satisfies the condition of |c|(DA+DB)/2,f(c,p)=0 may be achieved irrespective of the value of the jetting timedifference p.

The surrounding dots of which the jetting time difference is equal to orgreater than two scanning paths may be excluded from the targets usingthe jetting time difference p. That is, in a case where p is equal to orgreater than two scanning paths, f(c,p)=0 may be achieved irrespectiveof the value of the inter-dot distance c. As the jetting timedifference, a scanning path difference may be used.

That is, inter-dot contact determination means for determining whetheror not the dots are in contact with each other based on at least any oneof the inter-dot distance c or the jetting time difference p may beprovided, and the simulation image generation functioning as simulationimage generation means may generate the simulation image acquired byreflecting the influence of the landing interference on the dotsdetermined to be in contact with each other by the inter-dot contactdetermination means.

As the reflection of the landing interference, at least any one of thedensity change of the dot or the shape change of the dot in addition tothe dot movement or instead of the dot movement may be adopted.Hereinafter, the reflection of the influence of the landing interferenceincluding the shape of the dot and the density of the dot will bedescribed.

FIG. 62A is a conceptual diagram showing the change due to the landinginterference including the shape of the dot, and is a diagram showingthe relationship between an inter-density-maximum-point distance and aninter-center distance of two dots in a case where the landinginterference does not occur. FIG. 62B is a conceptual diagram showingthe change due to the landing interference including the shape of thedot, and is a diagram showing the relationship between aninter-density-maximum-point distance and an inter-center distance of twodots in a case where the landing interference occurs.

FIG. 63 is a schematic diagram of the dot when the dot of FIG. 62B isviewed from the top.

As shown in FIG. 62A, an inter-center distance d_(AB) between two dotsDotA and DotB jetted at the same jetting timing in a case where thelanding interference does not occur is substantially the same as adistance e_(AB) between a maximum density point of the dot DotA and amaximum density point of the dot DotB.

It is assumed that the maximum density point of the dot is a positionindicating the maximum density in a case where the dot is viewed fromthe top and is equal to the center of the dot in a case where thedeformation of the dot does not occur. That is, in a case where the dotsDotA and DotB are viewed from the top, the densities of the dots DotAand DotB are uniformly distributed on the concentric circles from thecenters OA and OB of the dots with the centers OA and OB of the dots asthe maximum densities.

In contrast, as shown in FIG. 62B, if the dots DotA and DotB aredeformed due to the occurrence of the landing interference, the otherdot is drawn toward one dot. By doing this, the inter-center distance ofthe dot is changed to u_(AB) (u_(AB)<d_(AB)) shown in FIG. 62B fromd_(AB) shown in FIG. 62A.

The inter-density-maximum-point distance between the dots DotA and DotBis changed to v_(AB) (v_(AB)<e_(AB), v_(AB)<u_(AB)) shown in FIG. 62Bfrom e_(AB) shown in FIG. 62A. A position denoted by reference numeralDenA in FIG. 63 is the maximum density point of the dot DotA in a casewhere the landing interference occurs.

If the other dot is drawn toward the one dot due to the occurrence ofthe landing interference, the density maximum positions of both dots arealso drawn toward each other, and the density distribution is changed.In FIG. 63, the density distribution (equi-density position) of the dotDotA is schematically shown using a dashed double-dotted line. In FIG.63, since the maximum density point and density distribution of the dotDotB are the same as those of the dot DotA, the illustration of themaximum density point and density distribution of the dot DotB isomitted.

That is, if the other dot is drawn toward one dot due to the occurrenceof the landing interference, the density of the region where both thedots overlap each other is relatively high, and the density of a regionopposite to the region where both the dots overlap each other isrelatively low.

The generation of the simulation image in which the density change ofthe dot and the shape change of the dot are reflected may be performedthrough the following procedures.

Initially, the movement of the maximum density point due to the landinginterference is defined by a function g(c,p) using the inter-dotdistance c and the jetting time difference p as the parameters.Similarly to the function f(c,p), the functions g(c,p) are classifiedfor each color and each droplet kind of the given dot and each color andeach droplet kind of the surrounding dot. Since the inter-dot distance cis the vector having the direction, the function g(c,p) is the vectorhaving the direction.

The movement of the dot due to the landing interference is calculatedusing Expression (11) to Expression (14), and the dots are rearranged.The movement of the maximum density point is calculated as the summationof the functions g(c,p), and the dots are rearranged. If the movement ofthe dot and the movement of the maximum density point of the dot aredetermined, since the shape of the dot is acquired, the shape of the dotis replaced with the acquired dot shape. The shape of the dot mentionedherein refers to a three-dimensional shape acquired by adding a shape ina thickness direction to a planar shape when viewed from the top.

The rearrangement of the dots due to the movement of the dot and therearrangement of the dots due to the movement of the density maximumposition of the dot may be changed.

By doing this, the simulation image in which the shape change of the dotdue to the influence of the landing interference and the density changeof the dot are reflected may be generated.

As for the movement of the dot due to the influence of the landinginterference, after the jetting is performed along the k-th scanningpath, the landing interference due to the dots jetted along the firstscanning path to the (k−1)-th scanning path is reflected on the dotsjetted along the k-th scanning path, the landing interference due to thedots jetted along the k-th scanning path is not reflected on the dotsjetted along the first scanning path to the (k−1)-th scanning path.

In other words, after the jetting is performed along the k-th scanningpath, the dots jetted along the k-th scanning path are moved, but thedots jetted along the first scanning path to the (k−1)-th scanning pathare not moved. This is because the drying and fixing of the dots jettedalong the first scanning path to the (k−1)-th scanning path progress ata jetting timing of the k-th scanning path.

However, among the dots jetted along the first path to the (k−1)-thpath, the landing interference due to the dots jetted along the k-thscanning path may be reflected on the dots jetted along the scanningpath (for example, the (k−1)-th scanning path or the (k−2)-th scanningpath) close to the k-th scanning path.

That is, among the dots jetted along the first scanning path to the(k−1)-th scanning path, the movement of the dot may be calculated forthe dots jetted the scanning path close to the k-th scanning path byusing Expression (11) to Expression (14), and the dots may berearranged.

It has been described in the present embodiment that the dots arearranged by reflecting the characteristic parameter other than thelanding interference, the movement of the dot in which the influence ofthe landing interference is reflected on the dot arrangement iscalculated, and the dots are rearranged. However, the reflection of thecharacteristic parameter other than the landing interference and thereflection of the landing interference may be collectively performedwithout performing the dot arrangement in which the characteristicparameter other than the landing interference is reflected.

Although it has been described in the present embodiment that themagenta and the black are taken into consideration, the light ink suchas cyan, yellow, light cyan or light magenta, and the special color inksuch as orange, green or violet may be taken into consideration.

As an example in which the color is expanded, there is an aspect inwhich the functions f(c,p) indicating the movement of the dot shown inExpression (11) to Expression (14) and the functions g(c,p) indicatingthe movement of the maximum density point of the dot are expanded.

The dots may be rearranged using only color in which the influence ofthe landing interference, the dot density change and the dot shapechange is strong as a target. Among a plurality of processes ofreflecting the influence of the landing interference described above, atleast one process may be performed according to the state of the landinginterference and the state of the printing system.

[Specific Example of Means for Applying Tolerance to LandingInterference]

A specific example of a configuration in which the halftone design orthe halftone process of controlling the image quality deterioration dueto the landing interference is realized will be described.

In the present specification, the outline of the “means for compensatingfor the image quality deterioration due to the influence of the landinginterference” has been already described, and the generation of thehalftone parameter or the method of the halftone process of suppressingthe image quality deterioration due to the dot movement at the time ofthe landing interference has been mentioned. Here, a specific example ofmeans for applying the tolerance to the landing interference will bedescribed in more detail.

Means for suppressing the image quality deterioration due to the landinginterference analyzes the contact state of each dot with anotheradjacent dot (that is, surrounding dot) from the data of the dot imageindicating the dot arrangement form of the plurality of pixels,evaluates the influence of the landing interference, and performs thegeneration (that is, the halftone design) of the halftone parameter orthe halftone process such that the tolerance to the landing interferencebased on the evaluating result.

As the form for realizing such a function, some forms are considered.Here, the processing content of the halftone design or the halftoneprocess performed such that the movement amount of the dot due to thelanding interference is estimated based on the contact direction and thecontact amount of each dot with the surrounding dot and the movementamount (that is, the influence of the landing interference) is decreasedas a whole will be described. Even though the landing interferenceoccurs, the halftone image in which the movement of the dot due to theinfluence is relatively less is acquired by performing the halftonedesign or the halftone process.

Three examples of an example of the process of generating the halftoneparameter in the dither method or the error diffusion method, an exampleof the process of generating the halftone parameter by thevoid-and-cluster with respect to the dither method, and an example ofthe halftone process in the direct binary search method will bedescribed by referring to FIGS. 10, 14 and 16 already described.

FIG. 64 is a flowchart related to the process of generating the halftoneparameter in the dither method or the error diffusion method.

The flowchart shown in FIG. 64 may be adopted instead of the flowchartdescribed in FIG. 10.

The flowchart shown in FIG. 64 is a common flowchart in both the dithermethod and the error diffusion method. Here, the dither method will bedescribed as an example.

Initially, the halftone parameter is temporarily set (step S501). In thedither method, the setting of the respective threshold values of thedither mask corresponds to the determination of the halftone parameter.The flowchart of FIG. 64 is repeatedly performed with a threshold valuefrom 0 to maximum value.

In step S501, after the halftone parameter is temporarily set, thehalftone process is subsequently performed using the temporarily sethalftone parameter (step S502). In the dither method, step S502corresponds to the acquisition of the dot-ON pixels from a thresholdvalue “0” to a current threshold value. That is, this step correspondsto the acquisition of the halftone image (dot arrangement) acquired byperforming the halftone process of applying the dither mask to the inputimage of a single gradation having a current-threshold value gradation.

Subsequently, the image quality of the halftone image generated in stepS502 is evaluated (step S503). Although it has been described in theflowchart of FIG. 10 that the simulation image is generated using thecharacteristic parameters related to the characteristics of the printingsystem when the image quality is evaluated (step S28) (step S26 of FIG.10).

However, the generation of the simulation image is not an essentialprocess when the image quality is evaluated (step S503) in the flowchartshown in FIG. 64. That is, the image quality of the halftone imagegenerated by the halftone process of step S502 may be evaluated.

It is assumed that when the image quality is evaluated in step S503,even in a case where the simulation is performed in consideration of thecharacteristic parameters of the system as shown in the example of FIG.10, the simulation related to the influence of the landing interferencedescribed in FIG. 11 is not performed. This is because the influence ofthe landing interference is separately evaluated in step S504 of FIG.64.

The image quality evaluation of step S503 is performed by calculating atleast one evaluation value of a value acquired by applying a low-passfilter such as a Gaussian filter or a visual transfer function (VTF)representing human visual sensitivity to the halftone image, performingfrequency conversion and performing integral calculus, root means square(RMS) granularity, or an error or a standard deviation with the inputimage. The value calculated in the image quality evaluating process ofstep S503 is stored as an “image quality evaluation value” in thememory.

Subsequently, the landing interference influence is evaluated (stepS504). Based on the evaluating result of the landing interferenceinfluence and the evaluating result of the image quality evaluationacquired in step S503, it is determined whether or not the halftoneparameter is updated, and the halftone parameter is updated (step S505).

The flowchart of FIG. 64 is greatly different from the flowchart of FIG.10 in that the steps of step S504 and step S505 are performed. The moredetailed processing contents of step S504 and step S505 of FIG. 64 aredescribed below.

In step S506 of FIG. 64, it is determined whether or not the steps ofstep s501 to step S505 are repeatedly performed a predetermined numberof times. The “predetermined number of times” of step S506 in the dithermethod is the number of all pixels of candidates corresponding to thethreshold value.

If the process is performed the predetermined number of times and theprocess is not completed in the determination of step S506, the stepreturns to step S501, and the steps of step S501 to step S505 arerepeated. In the determination of step S506, if the process is performedthe predetermined number of times and the process is completed, theprocess is ended.

FIG. 65 is a flowchart showing an example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

Step S511 to step S514 of FIG. 65 correspond to the process of step S504of FIG. 64, and step S515 of FIG. 65 corresponds to the process of stepS505 of FIG. 64.

As shown in FIG. 65, the movement direction and the movement amount dueto the landing interference are initially calculated based on thecontact direction and contact amount of each dot of the plurality ofdots included in the halftone image with the surrounding dot (stepS511).

FIG. 66 is an explanatory diagram for describing the method ofcalculating the movement direction and movement amount of the dotmovement due to the landing interference. Each cell of a grid of FIG. 66represents a pixel. A rectangular coordinate system is introduced into atwo-dimensional grid shown in FIG. 39, a horizontal direction of FIG. 66is described an X direction, and a vertical direction is described as aY direction. Here, the Y direction corresponds to the paper transportdirection.

A circle denoted by a broken line of FIG. 66 represents a spreadingregion of the dot. In FIG. 66, the numerals “1” to “6” described in thecells represent dot numbers. The respective dots are assigned the dotnumbers in such a manner that the dot having a number of 1 is “Dot1” andthe dot having a number of 2 is “Dot2”.

The movement directions and the movement amounts of the dots calculatedbased on the contact directions and the contact amounts of the dotshaving the dot number from 1 to 6 shown in FIG. 66 with the surroundingdots are represented for the dots by arrows. The direction indicated bythe arrowhead of the arrow represents the movement direction of the dot,and the length of the arrow represents the magnitude of the movementamount. The movement direction and the movement amount of the dot due tothe landing interference may be treated as the vectors. That is, themovement amount of each dot due to the landing interference may beexpressed as a vector quantity having the magnitudes of the movementdirection and the movement amount.

The range of the surrounding dot is a range in which the landinginterference may occur, that is, a range in which there is a possibilitythat the adjacent dots will overlap each other. The larger the dot, thewider the range of the surrounding dot.

For example, the “contact direction” may be classified into any one of 8directions of a left direction, a right direction, an up direction, adown direction, an upper left direction, a lower left direction, anupper right direction and a lower right direction. Of course, thecontact direction may be classified into directions more minutely orroughly than 8 directions.

The “contact amount” depends on the size of the dot and the distancebetween the centers of the dots. The contact amount may be simplyexpressed by the distance between the centers of the dots. The “contactamount” may be expressed by the distance at which the dots overlap in aline that connects the centers of the dots, or may be expressed by thearea with which the dots overlap. For example, in a case where thediameter of Dot 1 is D₁, the diameter of Dot 2 is D₂, and the size ofone pixel in the X direction is p_(x), the distance between the centersof Dot 1 and Dot 2 is p_(x), and the distance at which the dots overlapin the line that connects the centers of Dot 1 and Dot 2 may beexpressed by (D₁/2)+(D₂/2)−p_(x).

The dot arrangement form in the given halftone image is analyzed, andthus, it is possible to comprehend the contact direction and the contactamount of each dot with the surrounding dot. It is possible to estimatethe movement direction and the movement amount of the dot due to thelanding interference based on information of the contact direction andthe contact amount of each dot with the surrounding dot.

Since Dot 1 is in contact with Dot 2 formed by the adjacent pixel on theright, the movement direction of Dot 1 with Dot 2 due to the landinginterference is a right direction of FIG. 66, and the movement amountdue to the landing interference is the magnitude depending on thecontact amount. In FIG. 66, the moving vector indicating the movementdirection and the movement amount of Dot 1 due to the landinginterference is expressed by Mv12. In a case where i and j are integersindicating the dot numbers, the movement vector of Dot i with Dot j dueto the landing interference is described as Mvij. The magnitude of themovement vector Mvij is described as |Mvij|. The |Mvij| refers to theabsolute value of the movement amount of Dot i with Dot j due to thelanding interference.

In the case of Dot 2, the landing interference with Dot 1 and thelanding interference with Dot 3 are offset, and there is “no movement”.That is, in the case of Dot 2, a movement vector Mv21 with Dot 1 due tothe landing interference and a movement vector Mv23 with Dot 3 due tothe landing interference have directions opposite to each other and havethe same magnitude. Accordingly, a movement vector Mv2 of Dot 2 due tothe landing interference is expressed as the vector sum of the movementvector Mv21 and the movement vector Mv23 (Mv2=Mv21+Mv23), the influenceof the landing interference is offset, and there is no movement. Thatis, |Mv2|=|Mv2|+Mv23|=0.

Since Dot 3 is in contact with Dot 2 positioned adjacent on the left,the movement direction of Dot 3 with Dot 2 due to the landinginterference is the left direction of FIG. 66, and the movement amounthas the magnitude corresponding to the contact amount. In FIG. 66, themovement vector of Dot 3 is expressed as Mv32.

Since Dot 4 is in contact with Dot 5 positioned adjacent in the upperright direction, the movement direction of Dot 4 with Dot 5 due to thelanding interference is the upper right direction, and the movementamount has the magnitude corresponding to the contact amount. In FIG.66, the movement vector of Dot 4 is expressed as Mv45. Since the contactamount of Dot 4 with Dot 5 is smaller than the contact amount of Dot 1with Dot 2, the movement amount |Mv45| of Dot 4 is smaller than themovement amount |Mv12| of Dot 1.

Dot 5 is in contact with Dot 4 and Dot 6. In the case of Dot 5, as avector sum acquired by combining a movement vector Mv54 with Dot 4adjacent in the lower left direction due to the landing interference anda movement vector Mv56 with Dot 6 adjacent in the lower right directiondue to the landing interference, a movement vector Mv5=Mv54+Mv56. Asshown in FIG. 66, the movement direction of the movement vector Mv5 ofDot 5 is the down direction, and the movement amount |Mv5| of Dot 5 maybe expressed as |Mv5|=|Mv54|×2^(1/2).

Since Dot 6 is in contact with Dot 5 positioned adjacent in the upperleft direction, the movement direction of Dot 6 with Dot 5 due to thelanding interference is the upper left direction, and the movementamount has the magnitude corresponding to the contact amount. In FIG.66, the movement vector of Dot 6 is expressed as Mv65.

Bo doing this, the movement vectors of each dot of the halftone imagewith the surrounding dots due to the landing interference are acquired,and Summation A of the movement amounts of each dot due to the landinginterference is calculated (step S512 of FIG. 65).

Summation A of the movement amounts calculated in step S512 indicatesthe summation of the absolute values of the movement amounts of each dotdue to the influence of the landing interference in a state in which theparameter of the error of the printing system is not added.

In FIG. 66, the summation is expressed by SummationA=|Mv12|+|Mv2|+|Mv32|+|Mv45|+|Mv5|+|Mv65|.

Subsequently, the movement amount of each dot in the dot arrangement inwhich at least one error of the dot diameter, the dot shape, the dotforming position shift or the non-jetting is reflected due to thelanding interference is calculated (step S513 of FIG. 65).

Here, in order to simplify the description, an example of the dotforming position shift will be described as the kind of reflected error.FIG. 67 shows an example of the dot arrangement on which the error dueto the dot forming position shift of the specific nozzle of therecording head is reflected. In FIG. 67, a case where the dot formingposition shift occurs in the nozzle serving to record Dot 2 and Dot 5 isshown.

FIG. 67 shows that the landing positions of Dot 2 and Dot 5 due to thedot forming position shift are shifted in the left direction of FIG. 67.The direction of the dot forming position and the shift amount of thelanding position are specified by the parameter indicating the error ofthe dot forming position shift. The shift amount of the landing positiondue to the dot forming position shift is referred to as a “dot formingposition shift amount”. In the example of FIG. 67, the direction of thedot forming position shift is a “−X direction”, and the dot formingposition shift amount is ½ pixel. The dot forming position shift amountof “½ pixel” refers to p_(x)/2 using p_(x) which is the size of onepixel in the X direction as a unit.

The movement amount due to the landing interference is calculated basedon the contact direction and the contact amount of each dot in the dotarrangement shown in FIG. 67 with the surrounding dot.

Dot 1 in FIG. 67 is in contact with Dot 2 positioned adjacent on theright. The landing position of Dot 2 to which the error of the dotforming position shift is added is moved in a direction close to Dot 1unlike a state (state in which there is no dot forming position shift)before the error described in FIG. 66 is added. Accordingly, in FIG. 67,the contact amount of Dot 1 with Dot 2 has a value greater than thecontact amount in FIG. 67.

In FIG. 67, the movement vector of Dot 1 with Dot 2 due to the landinginterference is expressed as Me12. When the movement vector of each dotin the dot arrangement to which the error of the dot forming positionshift is added due to the influence of the landing interference isdescribed, in a case where i and j are integers indicating the dotnumbers, the movement vector of Dot i with Dot j due to the landinginterference is described as Meij. The magnitude of the movement vectoris described as |Meij|.

The magnitude |Me12| of the movement vector Me12 of Dot 1 shown in FIG.67 is greater than the magnitude |Mv12| of the movement vector Mv12 ofDot 1 described in FIG. 39.

In the case of Dot 2 in FIG. 67, the movement vector Me21 with Dot 1 dueto the landing interference and the movement vector Me23 with Dot 3 dueto the landing interference have directions opposite to each other, andhave the magnitude of |Me21|>|Me23|. Accordingly, in the case of Dot 2,the movement vector Me21 and the movement vector Me23 are combined, andas the vector sum thereof, the movement vector Me2=Me21+Me23.

Dot 3 in FIG. 67 is in contact with Dot 2 positioned adjacent on theleft, but the contact amount due to the dot forming position shift ofDot 2 is smaller than that in the example of FIG. 66. Accordingly, themovement direction of Dot 3 of FIG. 67 with Dot 2 due to the landinginterference is the left direction, and the movement amount has themagnitude corresponding to the contact amount. In FIG. 67, the movementvector of Dot 3 is expressed as Me32.

Dot 4 in FIG. 67 is in contact with Dot 5 in which the dot formingposition shift occurs. The contact amount of Dot 4 with Dot 5 due to thedot forming position shift of Dot 5 is more increased than the contactamount of Dot 4 with Dot 5 described in FIG. 66. In FIG. 67, themovement vector of Dot 4 is expressed as Me45. The magnitude |Me45| ofthe movement vector Me45 of Dot 4 shown in FIG. 67 is greater than themagnitude |Mv45| of the movement vector Mv45 of Dot 4 described in FIG.66.

Dot 5 in FIG. 67 is not in contact with Dot 6 due to the dot formingposition shift, and is in contact with only Dot 4. Thus, the movementvector Me54 of Dot 5 of FIG. 67 with Dot 4 due to the landinginterference is acquired.

Since Dot 6 of FIG. 67 is not in contact with another surrounding dot,the landing interference of Dot 6 does not occur, and the movementamount due to the influence of the landing interference is “0”. That is,the magnitude of the movement vector Me6 of Dot 6 due to the landinginterference is |Me6|=0, and there is “no movement amount”.

By doing this, the movement vector of each dot of the halftone image towhich the predetermined error is added with the surrounding dot due tothe landing interference is calculated (step S513), and Summation B ofthe absolute values of the movement amounts of each dot due to thelanding interference is calculated (step S514 of FIG. 65).

Summation B of the movement amounts calculated in step S514 indicatesthe summation of the absolute values of the movement amounts of each dotdue to the influence of the landing interference in a state in which theparameter of the error of the printing system is reflected.

In FIG. 67, the summation may be expressed by SummationB=|Me12|+|Me2|+|Me32|+|Me45|+|Me54|+|Me6|.

Through the steps from step S511 to step S514 of FIG. 65, the summationof the absolute values of the movement amounts of each dot due to thelanding interference is calculated in the state of “no dot formingposition shift” described in FIG. 66 and the state of “dot formingposition shift” described in FIG. 67. That is, Summation A of theabsolute values of the movement amount of each dot due to the landinginterference in the state of “no dot forming position shift” which isthe state in which the error of the dot forming position shift is notadded and summation B of the absolute values of the movement amounts ofeach dot due to the landing interference in the state of “dot formingposition shift” which is the state in which the error of the dot formingposition shift is added are calculated. FIG. 66 corresponds to the statebefore the error reflection, and FIG. 67 corresponds to the state afterthe error reflection.

Summation A and Summation B correspond to forms of “landing interferenceevaluation values”. Summation A and Summation B are evaluation valuesacquired by adding the movement amounts of each dot due to the landinginterference, and are respectively indices indicating the entire degreeof influence of the dot movement due to the landing interference. Thedegree of influence of the landing interference are quantified as valuesby Summation A and Summation B.

Summation A corresponds to one example of a “first landing interferenceevaluation value”, and Summation B corresponds to one example of a“second landing interference evaluation value”.

The process proceeds to step S515 after step S514 of FIG. 65. Step S515includes a determining process of determining whether or not to updatethe halftone parameter, and an updating process based on the determiningresult.

That is, in step S515, the process of comparing Summation A andSummation B of the movement amounts with the specified reference valueand updating the halftone parameter in a case where Summation A andSummation B are equal to or less than the specified reference value andthe image quality evaluation value calculated in step S503 of FIG. 64 isenhanced is performed. The process of comparing Summation A andSummation B with the specified reference value corresponds to oneexample of a “comparison process”. The determination of whether or notSummation A and Summation B are equal to or less than the specifiedreference value is performed based on the “comparing result” of thecomparison process.

The specified reference value mentioned here is a value that determinesan allowable upper limit of the influence of the dot movement due to thelanding interference, and is previously determined in a range in whichthe image quality deterioration due to the landing interference falls inan allowable level. A case where Summation A and Summation B are equalto or less than the specified reference value means that the influenceof the dot movement due to the landing interference is equal to or lessthan the influence of the dot movement expressed by the reference value.

In step S515, it is determined whether or not to update the halftoneparameter by combining Summation A and Summation B of the movementamounts with the image quality evaluation value calculated in step S503of FIG. 64.

The “halftone parameter being updated” means that the halftone parameteris updated by adopting the halftone parameter temporarily set in stepS501 of FIG. 64.

According to the configuration described in FIGS. 64 to 67, it ispossible to generate the halftone parameter such that the dotarrangement falls in the allowable range represented by the specifiedreference value based on the comparing result of the process ofcomparing Summation A and Summation B of the movement amounts which arethe landing interference evaluation values with the specified referencevalue.

FIG. 68 is a block diagram of major parts for describing the function ofan image processing device according to a tenth embodiment. In FIG. 68,the same or similar elements as or to those of the configurationdescribed in FIG. 3 will be assigned to the same reference numerals, andthe description thereof will be omitted.

The image processing device 20 according to the tenth embodiment shownin FIG. 68 has functions of performing the processes described in FIGS.64 to 67. That is, the image processing device 20 shown in FIG. 68includes a halftone image analysis unit 532, a dot-movement-amountcalculation unit 534, a landing-interference-influence evaluation unit536, a reference value storage unit 538, a halftone process generationunit 58, a halftone-processing-rule storage unit 60, a halftoneprocessing unit 80, and a data output unit 66. The image processingdevice 20 includes a parameter acquisition unit 544, and an errorreflection processing unit 546.

The halftone image analysis unit 532 analyzes data of a halftone image550, and generates information of a contact direction and a contactamount of each dot of the halftone image 550 with a surrounding dotwhich is another dot. The halftone image analysis unit 532 correspondsto one example of “analysis means”. The process of causing the halftoneimage analysis unit 532 to analyze a contact state of the dots and togenerate information of the contact direction and contact amountindicating the contact state corresponds to one example of an “analysisprocess”. The processing function of the halftone image analysis unit532 corresponds to one example of an “analysis function”.

The halftone image 550 is the dot image generated during the process ofcausing the halftone process generation unit 58 to determine thehalftone parameter. The dot image refers to an image indicating a dotarrangement form. The halftone image 550 is generated in the process ofstep S502 of FIG. 64.

The dot-movement-amount calculation unit 534 calculates a movementdirection and a movement amount of the dot movement of each dot due tothe landing interference based on the information of the contactdirection and contact amount of each dot acquired from the halftoneimage analysis unit 532 with the surrounding dot. Thedot-movement-amount calculation unit 534 corresponds to one example of“movement amount calculation means”. The process of causing thedot-movement-amount calculation unit 534 to calculate the movementamount of the dot movement corresponds to one example of a movementamount calculation step. The processing function of thedot-movement-amount calculation unit 534 corresponds to one example of amovement amount calculation function.

The landing-interference-influence evaluation unit 536 calculates alanding interference evaluation value for quantitatively evaluating theinfluence of the dot movement due to the landing interference from theinformation indicating the movement direction and the movement amountacquired by the dot-movement-amount calculation unit 534. Thelanding-interference-influence evaluation unit 536 corresponds to oneexample of “landing-interference-influence evaluation means”. Theprocess of causing the landing-interference-influence evaluation unit536 to calculate the landing interference evaluation value correspondsto one example of a “landing-interference-influence evaluating process”.The processing function of the landing-interference-influence evaluationunit 536 corresponds to one example of a “landing-interference-influenceevaluation function”.

Summation A and Summation B described in FIG. 65 are forms of “landinginterference evaluation values”. The landing-interference-influenceevaluation unit 536 calculates Summation A and Summation B described inFIG. 65.

The reference value storage unit 538 is storage means for storinginformation of a specified reference value described in step S515 ofFIG. 65. The landing-interference-influence evaluation unit 536 comparesSummation A and Summation B as the calculated landing interferenceevaluation values with the specified reference value, and determines thedegree of influence of the dot movement due to the landing interference.

The halftone process generation unit 58 generates the halftoneprocessing rule in cooperation with the landing-interference-influenceevaluation unit 536.

The parameter acquisition unit 544 is means for acquiring a parameterindicating at least one error of the dot diameter, the dot formingposition shift or the non-jetting. In the example described in FIG. 67,a parameter indicating a dot forming position shift direction and a dotforming position shift amount related to the error of the dot formingposition shift is acquired. The parameter acquisition unit 544 may be auser interface, may be a communication interface or a data receptionterminal that receives parameter information retained in an externalstorage medium or within the device, or may be an appropriatecombination thereof.

The error reflection processing unit 546 performs a process ofgenerating the arrangement of dots on which the error represented by theparameter acquired from the parameter acquisition unit 544 is reflected.

The error reflection processing unit 546 reflects the error representedby the parameter acquired from the parameter acquisition unit 544 on thedata of the halftone image 550, and generates a dot image indicating adot arrangement state after the error reflection. In the exampledescribed in FIG. 67, the error reflection processing unit 546 generatesdata of the dot arrangement to which the error due to the dot formingposition shift is added. The error reflection processing unit 546corresponds to one example of “error reflection processing means”.

The halftone image analysis unit 532 may perform analysis the contactdirection and the contact amount on the halftone image 550 before theerror is added by the error reflection processing unit 546 and anafter-error-reflection halftone image acquired by adding the error tothe halftone image 550 by means of the error reflection processing unit546.

A state before the error is added corresponds to one example of a “casewhere the non-reflection of the error is performed”. A state after theerror is added” corresponds to one example of a “case where the error isreflected”.

The process of step S511 of FIG. 65 is performed by the halftone imageanalysis unit 532 and the dot-movement-amount calculation unit 534. Theprocess of the step S513 of FIG. 65 is performed by combining theparameter acquisition unit 544, the error reflection processing unit546, the halftone image analysis unit 532 and the dot-movement-amountcalculation unit 534.

The steps of step S512 and step S514 of FIG. 65 are performed by thelanding-interference-influence evaluation unit 536. The process of stepS515 of FIG. 65 is performed by the landing-interference-influenceevaluation unit 536 and the halftone process generation unit 58.

In such a configuration, the halftone process generation unit 58 (seeFIG. 68) corresponds to one example of “signal processing means”, andthe step of causing the halftone process generation unit 58 to generatethe halftone parameter corresponds to one example of a “signalprocessing step”. The processing function of the halftone processgeneration unit 58 corresponds to one example of a “signal processingfunction”.

In addition to the configuration described in FIG. 68, the imageprocessing device 20 of FIG. 68 may have the same configuration as thatof the image quality evaluation processing unit 74 or thehalftone-selection-chart generation unit 76 described in FIG. 3.

<Case of Error Diffusion Method>

The flowchart of FIG. 64 may be applied to the generation of thehalftone parameter of the error diffusion method. Similarly to theexample described in FIG. 10, a diffusion coefficient of an errordiffusion matrix of each applied gradation section is determined byrepeatedly performing the flowchart of FIG. 64 on all the appliedgradation sections.

That is, it is assumed that an average value of the respectiveevaluation values of each gradation is used as an image qualityevaluation value by temporarily setting a diffusion coefficient of theerror diffusion matrix applied to a certain gradation section for thegradation section (step S501 of FIG. 64), performing the halftoneprocess on the input image (a uniform image of a single gradation) ofeach gradation of the gradation section (step S502 of FIG. 64), andevaluating the image quality of the halftone image (step S503). Theimage quality evaluation (step S503) is performed similarly to that inthe dither method.

The evaluation (step S504) of the landing interference influence and thehalftone parameter update determining and updating process (step S505)are performed similarly to those in the dither method.

<Case where Void-and-Cluster Method is Applied to Dither Method>

FIG. 69 is a flowchart in a case where the void-and-cluster method isused at the time of halftone design in the dither method. Instead of theflowchart described in FIG. 14, the flowchart shown in FIG. 69 may beadopted.

In the flowchart shown in FIG. 69, an initial halftone image isinitially prepared (step S521). The method of generating the initialhalftone image is the same as step S42 of FIG. 14.

Subsequently, the process proceeds to step S522 of FIG. 69, and a filteris applied to the halftone image. For example, as the filter, a low-passfiler such as a Gaussian filter is used. In step S522, the filter may beapplied to the halftone image, or the filter may be applied to thesimulation image in consideration of the characteristic parametersrelated to the characteristics of the printing system. However, it isassumed that even in a case where the simulation in consideration of thecharacteristic parameters is performed, the simulation related to theinfluence of the landing interference is not performed. This is becausethe influence of the landing interference is separately evaluated instep S523 of FIG. 69.

Subsequently, the landing interference influence is evaluated (stepS523). The halftone image is updated based on the evaluating result ofthe landing interference influence (step S524).

The more detailed contents of step S523 and step S524 of FIG. 69 aredescribed below.

In step S525, it is determined whether or not the setting (that is, thesetting of dots) of the threshold values for all the gradations iscompleted. If the setting thereof is not completed, the process proceedsto step S522, and the steps of step S522 to S524 are repeated. That is,the filter is applied to the halftone image to which the dots are newlyadded in step S522, and step S523 and step S524 are performed.

If the process of all the gradations is completed in step S525, and theprocess of FIG. 69 is ended.

FIG. 70 is a flowchart showing an example of the more detailedprocessing contents of step S523 and step S524 of FIG. 69. In theflowchart of FIG. 70, the same steps or similar steps as or to those ofthe flowchart described in FIG. 65 will be assigned to the same stepnumbers, and the description thereof will be omitted. The flowchart ofFIG. 70 includes the process of step S516 instead of step S515 of theflowchart described in FIG. 65.

Step S511 and step S514 of FIG. 70 correspond to the process of stepS523 of FIG. 69, and step S516 of FIG. 70 corresponds to the process ofstep S524 of FIG. 69.

In step S516 of FIG. 70, the threshold values are set to pixels of whichSummation A and Summation B of the movement amounts are respectivelyequal to or less than the specified reference value and which are theminimum-energy pixels (that is, void pixels) among the pixels of thehalftone image in which the dots are not set, and the dots are set tothe void pixels of the halftone image.

The flowchart shown in FIG. 70 is the process in a direction in whichthe threshold values are increased from the initial image, but a methodin which the threshold values (that is, gradation values) are decreasedfrom the initial image also follows the known void-and-cluster method.That is, a process of updating the halftone image by regarding themaximum-energy pixels among the pixels to which the dots are set ascluster pixels in which the dots are dense in the energy image acquiredby applying the filter to the halftone image, setting the thresholdvalues to the pixels and excluding the dots of the pixels issequentially repeated.

<Case where Halftone Process Using Direct Binary Search Method isPerformed>

FIG. 71 is a flowchart in a case where the halftone process using theDBS method is performed. The flowchart shown in FIG. 71 may be adoptedinstead of the flowchart described in FIG. 16.

In the flowchart shown in FIG. 71, an initial halftone image isinitially prepared (step S531).

The initial halftone image is separately generated by performing adither process using the halftone processing rule of the dither methodgenerated in step S14 of FIG. 4 or a simply generated dither mask.

Subsequently, a process of replacing the dots of the halftone image isperformed (step S532 of FIG. 71). The image quality is evaluated for thesimulation images generated before the dot replacement and after the dotreplacement (step S533).

The method of evaluating the image quality of step S533 may adopt thesame method as that of step S58 of FIG. 16. It has been described in theflowchart of FIG. 16 that the simulation images are generated using thecharacteristic parameters related to the characteristics of the printingsystem when the image quality is evaluated (step S58) (step S56 of FIG.16).

However, when the image quality is evaluated in the flowchart shown inFIG. 71 (step S533), the generation of the simulation image is not anessential process. That is, the image quality may be evaluated for thehalftone image without performing the simulation.

When the image quality is evaluated in step S533, it is assumed thateven in a case where the simulation in consideration of thecharacteristic parameters of the printing system is performed, thesimulation related to the influence of the landing interferencedescribed in FIG. 11 is not performed as in the example of FIG. 16. Thisis because the influence of the landing interference is separatelyevaluated in step S534 of FIG. 71.

Subsequently, the landing interference influence is evaluated (stepS534). The halftone image is updated by determining whether or not toupdate the halftone image based on the evaluating result of the landinginterference influence and the evaluating result of the image qualityevaluation acquired in step S533 (step S535). The more detailedprocessing contents of step S534 and step S535 of FIG. 71 are describedbelow.

The steps of step S532 and step S535 are repeated by performing the dotreplacement a predetermined number of times according to a preset “pixelupdating number of times”. That is, in step S536, it is determinedwhether or not the process of replacing the dots a predetermined numberof times is completed. In a case where the process is performed thepredetermined number of times, the process proceeds to step S532, andthe steps of step S532 to step S535 are repeated. In step S536, in acase where it is determined that the process is performed thepredetermined number of times, the process of FIG. 71 is ended.

FIG. 72 is a flowchart showing an example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71. Step S541 tostep S544 of FIG. 72 correspond to the process of step S534 of FIG. 71,and step S545 of FIG. 72 corresponds to the process of step S535 of FIG.71.

In step S541 of FIG. 72, the movement direction and the movement amountdue to the landing interference are calculated based on the contactdirection and contact amount of each dot with the surrounding dot foreach dot before the dot replacement and after the dot replacement.

Summation A of the movement amounts due to the landing interference iscalculated for each dot before the dot replacement and after the dotreplacement (step S542). The method of calculating the movement amountof each dot due to the landing interference and the method ofcalculating Summation A of the movement amounts are the same as those ofstep S511 and step S512 of FIG. 65 and the example described in FIG. 66.

Among Summations A acquired in step S542 of FIG. 72, the summation ofthe movement amounts due to the landing interference before the dotreplacement is described as “Summation A₁”, and the summation of themovement amounts due to the landing interference after the dotreplacement is described as “Summation A₂”.

Subsequently, the movement direction and the movement amount due to thelanding interference are calculated for each dot of the dot arrangementthat reflects at least one error of the dot diameter, the dot shape, thedot forming position shift or the non-jetting of each dot before the dotreplacement and after the dot replacement (step S543 of FIG. 72).

Summation B of the movement amounts due to the landing interference iscalculated for each dot before the dot replacement and after the dotreplacement (step S544). The method of calculating the movement amountof each dot due to the landing interference in a case where the error isreflected and the method of calculating Summation B of the movementamounts are the same as step S513 and step S514 of FIG. 65 and theexample described in FIG. 67.

Among Summations B acquired in step S544 of FIG. 72, the summation ofthe movement amounts due to the landing interference before the dotreplacement is described as “Summation B₁”, and the summation of themovement amounts due to the landing interference after the dotreplacement is described as “Summation B₂”.

The process proceeds to step S545 after step S544 of FIG. 72. Step S545includes a determining process of determining whether or not to updatethe halftone image, and an updating process based on the determiningresult. That is, in step S545, a process of respectively comparingSummation A and Summation B of the movement amounts calculated byreplacing the dots with the specified reference value and updating thehalftone image in a case where summation A and Summation B arerespectively equal to or less than the specified reference value and theimage quality evaluation value calculated in step S533 of FIG. 71 isenhanced before and after the dot replacement is performed.

That is, in step S545 of FIG. 72, it is determined whether or not toupdate the halftone image by combining Summation A2 and Summation B2 ofthe movement amounts due to the landing interference after the dotreplacement and the image quality evaluation value calculated in stepS533 of FIG. 71.

The “halftone image being updated” means that the halftone image isupdated by adopting the dot arrangement state in which the dots arereplaced by performing the dot replacement in step S532 of FIG. 71.

Through the process shown in FIGS. 71 and 72, it is possible to generatethe halftone image in which the dot movement amount due to the influenceof the landing interference is small.

The “dot movement amount being small” means that the degree of influenceof the dot movement is equal to or less than the degree of influence ofthe dot movement represented as the specified reference value.

According to the configuration described in FIGS. 71 and 72, it ispossible to generate the halftone image such that the dot arrangementfalls in the allowable range represented as the specified referencevalue based on the comparing result of the process of respectivelycomparing Summation A₂ and Summation B₂ of the movement amounts whichare the landing interference evaluation values with the specifiedreference value.

The halftone process described in FIGS. 71 and 72 may be performed bythe halftone processing unit 80 shown in FIG. 68. The halftone image 550as a target on which the landing interference influence evaluation inthis case is performed is the dot image generated during the processperformed by the halftone processing unit 80, and is the initial imagedescribed in step S531 of FIG. 71, the image after the dot replacementin step S532, or the updated halftone image that is updated in stepS535. The halftone processing unit 80 (see FIG. 68) that performs thehalftone process described in FIGS. 71 and 72 performs the updatingprocess on the halftone image using the DBS method in cooperation withthe landing-interference-influence evaluation unit 536.

In such a configuration, the halftone processing unit 80 (see FIG. 68)corresponds to one example of “signal processing means”, and the step ofcausing the halftone processing unit 80 to generate the halftone imagecorresponds to one example of a “signal processing step”. The processingfunction of the halftone processing unit 80 corresponds to one exampleof a “signal processing function”.

The processing content of the image processing device 20 according tothe embodiment described in FIGS. 64 to 72 described above may becomprehended as an image processing method.

Specific Modification Example Described in FIGS. 64 to 72 ModificationExample 1

In the description of FIGS. 64 to 72, the example in which the movementamount of the dot movement due to the landing interference is calculatedbased on the information indicating the contact direction and contactamount of each dot has been described. However, the movement amount ofthe dot movement due to the landing interference is treated to beapproximately proportional to the contact amount of the dot, and thus,it is possible to directly calculate the “landing interferenceevaluation value for evaluating the degree of influence of the dotmovement due to the landing interference” from the contact direction andthe contact amount.

For example, in the example of the dot arrangement shown in FIG. 73, acentral dot is paid attention to, the contact directions and the contactamounts of the central dot with left and right dots are depicted byarrows of FIG. 73. The directions indicated by the arrows represent thecontact directions, and the lengths of the arrows represent the contactamounts. The dot arrangement shown in FIG. 73 corresponds to thearrangement form of Dot 1, Dot 2 and Dot 3 described in FIG. 66.

In the contact state shown in FIG. 73, it can be seen that even thoughthe movement amount due to the landing interference is not calculated,since the sum of vectors depicted by two illustrated arrows is “0”, thelanding interference movement amount is “0”. Even though the calculationof the movement vector described in FIG. 66 is not performed, it ispossible to calculate the “landing interference evaluation value” fromthe summation of vectors indicating the contact directions and thecontact amounts with the surrounding dots.

Accordingly, it is possible to omit the “dot-movement-amount calculationunit 534” described in FIG. 68.

Modification Example 2

It has been described in each flowchart of FIGS. 65, 70 and 72 that theinfluence of the dot movement due to the landing interference issuppressed in a case where the predetermined error is reflected inaddition to the case where the predetermined error which is at least oneerror of the dot diameter, the dot shape, the dot forming position shiftor the non-jetting is not reflected.

However, when the invention is implemented, the present invention is notlimited to such a configuration, and the halftone design or the halftoneprocess may be performed such that the influence of the dot movement dueto the landing interference only in a case where the predetermined errormay be not reflected or only in a case where the predetermined error isreflected is suppressed. In order to suppress the influence of the dotmovement due to the landing interference in a case the predeterminederror is not reflected, Summation A may be equal to or less than thespecified reference value.

In order to suppress the influence of the dot movement due to thelanding interference in a case the predetermined error is reflected,Summation B may be equal to or less than the specified reference value.

The influence of the dot movement due to the landing interference in acase where the predetermined error is reflected is suppressed, and thus,it is possible to perform the halftone design or the halftone process inwhich the image quality is favorable in a state in which thepredetermined error is added or a deterioration in image quality is less(that is, there is the tolerance to the error) even though thepredetermined error is added.

Modification Example 3

It is preferable that the kind of the image as the target on which theimage quality evaluation is performed in a case where the image qualityevaluation is performed without performing the simulation related to thelanding interference in step S503 of FIG. 64 is the same as the kind ofthe image as the target on which the landing interference is performedin step S504. That is, it is preferable that it is determined whether ornot to reflect the dot diameter, the dot shape, the dot forming positionshift, the dot density, and various other errors on the evaluatingtarget images and the kinds and amounts of the errors to be reflectedare the same between the target image for evaluating the image qualityand the target image for evaluating the landing interference influencein a case where it is determined to reflect the errors on the evaluatingtarget image.

Similarly, it is preferable that the kind of the image to which thefilter is applied without performing the simulation related to thelanding interference in step S522 of FIG. 69 is the same as the kind ofthe evaluating target image of the landing interference influence instep S523.

That is, it is preferable that it is determined whether or not toreflect the dot diameter, the dot shape, the dot forming position shift,the dot density, and other various errors on the image acquired byapplying the filter without performing the simulation related to thelanding interference and the target image for evaluating the landinginterference influence and the kinds and amounts of the reflected errorsare the same between these images in a case where it is determined toreflect the errors on these images.

Similarly, it is preferable that the kind of the evaluating target imageof the image quality in a case where the image quality evaluation isperformed without performing the simulation related to the landinginterference in step S533 of FIG. 71 is the same as the kind of theevaluating target image of the landing interference influence in stepS534.

Modification Example 4

The updating reference of the halftone parameter of step S505 of FIG. 64or the updating reference of the halftone image of step S524 of FIG. 69or the step S535 of FIG. 71 is not limited to the updating referenceshown in step S515 of FIG. 65, step S516 of FIG. 70 or step S545 of FIG.72, and various updating references may be determined.

For example, the updating reference may be a “case where the imagequality evaluation value or the energy is equal to or less than apredetermined reference value for a determination reference and thelanding interference movement amount summation is enhanced” or a “casewhere a weighted sum of the image quality evaluation value or the energyand the landing interference movement amount summation is enhanced”. The“energy” mentioned herein corresponds to the image quality evaluationvalue of the energy image acquired by applying the filter such as aGaussian filter to the dot image.

The “landing interference movement amount summation” corresponds to oneexample of a “landing interference evaluation value”. The “landinginterference movement amount summation” may be “Summation A” and“Summation B” described in FIG. 65, 70 or 72, or may be a weightedsummation of Summation A and Summation B.

The “case where the landing interference movement amount summation isenhanced” means that an increase/decrease tendency indicating whetherthe value of the landing interference movement amount summation isincreased or decreased is comprehended, and it is determined that the“landing interference movement amount summation is enhanced” in a casewhere the landing interference movement amount summation is decreased.When it is determined whether or not the landing interference movementamount summation is enhanced, since it is comprehended whether thelanding interference movement amount summation is increased or decreasedby comparing the value of the landing interference movement amountsummation, a comparison process of comparing the landing interferencemovement amount summation is included. The determining result of whetheror not the landing interference movement amount summation is enhanced isbased on the “comparing result” of the comparison process.

The “weighted sum of the image quality evaluation value or the energyand the landing interference movement amount summation” corresponds toone example of an “evaluation value generated based on the landinginterference evaluation value”.

Modification Example 5

In a case where a predetermined error (however, an error other than thenon-jetting is used.) is reflected on the dot arrangement of thehalftone image, since the landing interference movement amount of thedot group on which the error is reflected is greatly changed unlike acase where the error is not reflected in most cases, the landinginterference movement amount of only the dot group on which the error isreflected may be evaluated. That is, in the example of FIG. 67, thesummation of the landing interference movement amounts of Dot 2 and Dot5 may be calculated as the landing interference movement amountsummation in a case where the error of the dot forming position shift isreflected.

“Each dot of the plurality of pixels” in a case where the landinginterference movement amount which is the movement amount of the dotmovement due to the landing interference is not limited to an aspect inwhich all the dots included in the dot image are used as targets, andsome dots of all the dots included in the dot image may be used astargets like an aspect in which only the dot group to which the error isadded is used as a target.

Modification Example 6

In a case where the dot forming position shift as the predeterminederror is reflected, since the landing interference movement amount in adirection parallel to the direction to which the error is added isgreatly changed in most cases, the landing interference movement amountin only the direction parallel to the direction to which the error isadded may be evaluated. In this case, for only the dots in contact inthe direction to which the error is added, that is, only the dotsincluding the dot movement in only the movement direction parallel tothe direction to which the error is added, the summation of the landinginterference movement amounts may be calculated, or the summation of thelanding interference movement amounts projected in a line in thedirection parallel to the direction to which the error is added may becalculated.

In the example shown in FIG. 67, the dots in contact in the direction towhich the error is added, that is, the dots including the dot movementin only the movement direction parallel to the direction to which theerror is added are Dot 1, Dot 2 and Dot 3. Accordingly, as the landinginterference movement amount summation, the summation of the movementamounts of the dot movement due of Dot 1, Dot 2 and Dot 3 to the landinginterference may be calculated.

Modification Example 7

In both the single path type ink jet printing system and the serial typeink jet printing system, in a case where the predetermined error isadded, the dot movement in a direction perpendicular to the scanningdirection on the paper greatly contributes to the occurrence of thestreak. The “scanning direction” refers to a direction in which the dotsare continuously jetted from the same nozzle. The “scanning direction”in the single path type is the paper transport direction, and the“scanning direction” in the serial type is the movement direction of thehead due to the carriage.

The “direction perpendicular to the scanning direction” in the singlepath type refers to a direction perpendicular to the paper transportdirection, that is, the main scanning direction which is the directionperpendicular to the sub scanning direction parallel to the papertransport direction.

The “direction perpendicular to the scanning direction” in the serialtype refers to a direction perpendicular to the movement direction ofthe head due to the carriage, that is, the sub scanning direction whichis the direction perpendicular to the main scanning direction parallelto the movement direction of the head due to the carriage.

Accordingly, in a case where the influence of the landing interferencein a state in which the predetermined error is added is evaluated, themovement amount of the dot movement in only the direction perpendicularto the scanning direction may be evaluated. In this case, for only thedots in contact in the direction perpendicular to the scanningdirection, that is, only the dots including the movement in only thedirection perpendicular to the scanning direction, the summation of thelanding interference movement amounts may be calculated, or thesummation of the landing interference movement amounts projected in linein the direction perpendicular to the scanning direction may becalculated.

In the example of FIG. 67, the “dots including the movement in only thedirection perpendicular to the scanning direction” are Dot 1, Dot 2 andDot 3. In FIG. 67, the direction to which the error is added due to thedot forming position shift is a direction parallel to the X direction,and the scanning direction is the Y direction. Accordingly, both thedirection to which the error is added and the direction perpendicular tothe scanning direction are equal to the direction parallel to the Xdirection.

[Another Specific Example of Means for Applying Tolerance to LandingInterference]

Hereinafter, another specific example of the configuration in which thehalftone design or the halftone process of suppressing the image qualitydeterioration due to the landing interference is realized will bedescribed.

Here, the processing content of the halftone design or the halftoneprocess in which the change (that is, the change of the influence of thelanding interference) of the dot movement due to the landinginterference before and after the error reflection is estimated based onthe contact direction and the contact amount of each dot with thesurrounding dot and the change of the dot movement before and after theerror reflection due to the landing interference is decreased will bedescribed. Through the halftone design or the halftone process, thetolerance to the error is exhibited, and thus, the halftone image inwhich even though the landing interference occurs, the image qualitydeterioration due to the influence thereof is relatively low isacquired.

<Application Example to Process of Generating Halftone Parameter inDither Method or Error Diffusion Method>

FIG. 74 is a flowchart showing another example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

Step S611 to step S614 of FIG. 74 correspond to the process of step S504of FIG. 64, and step S615 of FIG. 74 corresponds to the process of stepS505 of FIG. 64.

As shown in FIG. 74, the movement direction and the movement amount dueto the landing interference are calculated based on the contactdirection and the contact amount of each dot of the plurality of dotsincluded in the halftone image with the surrounding dot (step S611). Themethod described in FIG. 66 may be applied to the method of calculatingthe movement direction and the movement amount of the dot movement dueto the landing interference. As described in FIG. 66, the movementdirection and the movement amount due to the landing interference may beacquired from the contact direction and the contact amount of each dotof the halftone image with the surrounding dot (step S611 of FIG. 74).

Subsequently, the movement direction and the movement amount of each dotin the dot arrangement on which at least one error of the dot diameter,the dot shape, the dot forming position shift or the non-jetting isreflected due to the landing interference are calculated (step S612 ofFIG. 74). The method described in FIG. 67 may be applied to the methodof calculating the movement direction and the movement amount of eachdot in the dot arrangement on which the error is reflected due to thelanding interference. As described in FIG. 67, the movement directionand the movement amount due to the landing interference may be acquiredfrom the contact direction and the contact amount of each dot of thehalftone image in a state in which the predetermined error is added withthe surrounding dot (step S612 of FIG. 74).

Subsequently, the changes of the movement direction and the movementamount before and after the error reflection are calculated (step S613).The movement direction and the movement amount before the errorreflection are calculated by step S611. The movement direction and themovement amount after the error reflection are calculated by step S612.

FIG. 75 is an explanatory diagram for describing the method ofcalculating the changes of the movement direction and the movementamount before and after the error of the dot forming position shiftshown in FIGS. 66 and 67 is reflected.

The changes of the movement direction and the movement amount of eachdot of Dot 1 to Dot 6 described in FIGS. 66 and 67 before and after theerror reflection are as shown in FIG. 75. FIG. 66 corresponds to thestate before the error reflection, and FIG. 67 corresponds to the stateafter the error reflection.

In FIG. 75, a change vector indicating the changes of the movementdirection and the movement amount before and after the error reflectionon each dot is described as “Mdi”. A suffix i is an integer indicatingthe dot number. In the example of FIG. 75, i=1, 2, 3, . . . , and 6.

The changes of the movement direction and the movement amount before andafter the error reflection on each dot may be calculated as a differencebetween a before-error-reflection movement vector indicating themovement direction and the movement amount before the error reflectionand an after-error-reflection movement vector indicating the movementdirection and the movement amount after the error reflection.

In a case where the before-error-reflection movement vector of Dot i isdescribed as Mvi and the after-error-reflection movement vector thereofis described as Mei, the change vector Mdi of Dot i before and after theerror is reflected may be calculated by the expression of Mdi=Mei−Mvi.

The change vector Md1 indicating the changes of the movement directionand the movement mount of Dot 1 before and after the error reflectionmay be calculated by Md1=Me12−Mv12 as a difference between theafter-error-reflection movement vector Me12 shown in FIG. 67 and thebefore-error-reflection movement vector Mv12 shown in FIG. 66.

Similarly, the change vector Md2 of Dot 2 may be calculated byMd2=Me2−Mv2. The change vector Md3 of Dot 3 may be calculated byMd3=Me32−Mv32. The change vector Md4 of Dot 4 may be calculated byMd4=Me45−Mv45. The change vector Md5 of Dot 5 may be calculated byMd5=Me54−Mv5. The change vector Md6 of Dot 6 may be calculated byMd6=Me6−Mv65.

By doing this, the changes of the movement direction and the movementamount of each dot before and after the error reflection are calculated(step S613 of FIG. 74), and the summation of changes of the movementdirection and the movement amount before and after the error reflectionis calculated (step S614). The summation of the changes of the movementdirection and the movement amount before and after the error reflectioncalculated in step S614 is the summation of the absolute values of thechanges of the movement direction and the movement amount of each dotbefore and after the error reflection.

In FIG. 75, the summation of the changes of the movement direction andthe movement amount before and after the error is reflected may beexpressed by summation=|Md1|+|Md2|+|Md3|+|Md4|+|Md5|+|Md6|.

The “summation of the changes of the movement direction and the movementamount” calculated in step S614 corresponds to one example of a “landinginterference evaluation value”. The summation of the changes of themovement direction and the movement amount is an evaluation valueacquired by adding the changes of the movement direction and themovement amount of each dot, and is an index indicating the degree ofchange of the influence of the dot movement due to the landinginterference before and after the error reflection. The influence of thelanding interference is quantified as a value by the summation of thechanges.

The process proceeds to step S615 after step S614 of FIG. 74. Step S615includes a determining process of determining whether or not to updatethe halftone parameter, and an updating process based on the determiningresult. That is, in step S615, a process of comparing the summations ofthe changes of the movement direction and the movement amount with thespecified reference value and updating the halftone parameter in a casewhere the summations of the changes of the movement direction and themovement amount are equal to or less than the specified reference valueand the image quality evaluation value acquired in step S503 of FIG. 64is enhanced is performed.

The process of comparing the summation of the changes of the movementdirection and the movement amount with the specified reference valuecorresponds to one example of a “comparison process”. The determinationof whether or not the summation of the changes of the movement directionand the movement amount is equal to or less than the specified referencevalue is based on the “comparing result” of the comparison process.

The specified reference value is a value that determines an allowableupper limit of the change of the influence of the dot movement due tothe landing interference, and is previously determined in a range inwhich the image quality deterioration due to the landing interferencefalls in an allowable level. A case where the summation of the changesof the movement direction and the movement amount is equal to or lessthan the specified reference value means that the change of theinfluence of the dot movement due to the landing interference is equalto or less than the change of the influence of the dot movementrepresented by the reference value.

In step S615 of FIG. 74, it is determined whether or not to update thehalftone parameter by combining the summation of the changes of themovement direction and the movement amount with the image qualityevaluation value acquired in step S503 of FIG. 64.

The “halftone parameter being updated” means that the halftone parameteris updated by adopting the halftone parameter temporarily set in stepS501 of FIG. 64.

According to the configuration described in FIGS. 64, 66, 67, 74 and 75,it is possible to generate the halftone parameter which is the dotarrangement falling within the allowable range represented by thespecified reference value based on the comparing result of the processof comparing the summation of the movement direction and the movementamount which is the landing interference evaluation value with thespecified reference value.

FIG. 76 is a block diagram of major parts for describing the function ofan image processing device according to an eleventh embodiment. In FIG.76, the same or similar elements as or to those of the configurationdescribed in FIG. 3 will be assigned to the same reference numerals, andthe description thereof will be omitted.

The image processing device 20 according to the eleventh embodimentshown in FIG. 76 has functions of performing the processes described inFIGS. 64, 66, 67, 74 and 75. That is, the image processing device 20shown in FIG. 76 includes a halftone image analysis unit 532, adot-movement-amount calculation unit 534, a movement-amount-changecalculation unit 535, a landing-interference-influence evaluation unit536, a reference value storage unit 538, a parameter acquisition unit544, and an error reflection processing unit 546. The image processingdevice 20 includes a halftone process generation unit 58, ahalftone-processing-rule storage unit 60, a halftone processing unit 80,and a data output unit 66.

The parameter acquisition unit 544 is means for acquiring a parameterindicating at least one error of the dot diameter, the dot shape, thedot forming position shift or the non-jetting. In the example describedin FIG. 40, the parameters indicating a dot forming position shiftdirection and a dot forming position shift amount related to the errorsof the dot forming position shift are acquired. The parameteracquisition unit 544 may be a user interface, may be a communicationinterface or a data reception terminal that receives parameterinformation retained in an external storage medium or within the device,or may be an appropriate combination thereof.

The error reflection processing unit 546 performs a process ofgenerating the arrangement of dots that reflect the error represented bythe parameters acquired from the parameter acquisition unit 544.

The error reflection processing unit 546 reflects the errors representedby the parameters acquired from the parameter acquisition unit 544 onthe data of the halftone image 550, and generates a dot image indicatinga dot arrangement state after the error reflection. In the exampledescribed in FIG. 67, the error reflection processing unit 546 generatesdata of the dot arrangement to which the error due to the dot formingposition shift is added.

The halftone image 550 is the dot image generated during the process ofcausing the halftone process generation unit 58 to determine thehalftone parameter. The halftone image 550 is generated in the processof step S502 of FIG. 64. The halftone image 550 corresponds to oneexample of “first dot arrangement” which is the dot arrangement beforethe error is reflected.

The error reflection processing unit 546 corresponds to one example of“error reflection processing means”. The step of causing the errorreflection processing unit 546 to add the error to the dot of thehalftone image 550 and to generate the arrangement of the dots thatreflect the errors corresponds to one example of an “error reflectionprocessing step”. The dot image generated by reflecting the error on thehalftone image 550 by the error reflection processing unit 546corresponds to one example of “second dot arrangement”.

The halftone image analysis unit 532 includes a first halftone imageanalysis unit 532A, and a second halftone image analysis unit 532B. Thefirst halftone image analysis unit 532A analyzes the data of thehalftone image 550 which is the dot image before the error is reflectedby the error reflection processing unit 546, and generatesbefore-error-reflection contact state information 553A. Thebefore-error-reflection contact state information 553A is informationindicating the contact direction and contact amount of the dot asinformation depending on the contact state of the dots of the halftoneimage 550. That is, the first halftone image analysis unit 532A analyzesthe contact direction and contact amount of each of the plurality ofdots of the halftone image 550 with the surrounding dot which is anotherdot.

The first halftone image analysis unit 532A corresponds to one exampleof “first information generation means”, and corresponds to one exampleof “first analysis means”. The before-error-reflection contact stateinformation 553A acquired by the first halftone image analysis unit 532Acorresponds to one example of “first contact state information”, andcorresponds to “first information”. The step of causing the firsthalftone image analysis unit 532A to generate thebefore-error-reflection contact state information 553A corresponds toone example of a “first information generation step”.

The second halftone image analysis unit 532B analyzes the data of thehalftone image after the error is reflected on the halftone image 550 bythe error reflection processing unit 546, and generates theafter-error-reflection contact state information 553B. Theafter-error-reflection contact state information 553B is informationindicating the contact direction and the contact amount of the dot asinformation depending on the contact state of the dots of the halftoneimage after the error reflection. That is, the second halftone imageanalysis unit 532B analyzes the contact direction and the contact amountof each dot of the plurality of dots of the dot image after the errorreflection by the error reflection processing unit 546 with thesurrounding dot which is another dot.

The second halftone image analysis unit 532B corresponds to one exampleof “second information generation means”, and corresponds to one exampleof “second analysis means”. The after-error-reflection contact stateinformation 553B acquired by the second halftone image analysis unit532B corresponds to one example of “second contact state information”,and corresponds to one example of “second information”. The step ofcausing the second halftone image analysis unit 532B to generate theafter-error-reflection contact state information 553B corresponds to oneexample of a “second information generation step”.

The halftone image analysis unit 532 may analyze the contact directionand the contact amount for the halftone image 550 before the error isreflected by the error reflection processing unit 546 and theafter-error-reflection halftone image after the error is reflected onthe halftone image 550 by the error reflection processing unit 546.

The dot-movement-amount calculation unit 534 includes a firstdot-movement-amount calculation unit 534A, and a seconddot-movement-amount calculation unit 534B. The first dot-movement-amountcalculation unit 534A calculates the movement direction and the movementamount of the dot movement of each dot due to the landing interferencebased on the information of the contact direction and the contact amountwhich is the before-error-reflection contact state information 553Aacquired from the first halftone image analysis unit 532A. Theinformation indicating the movement direction and the movement amount ofthe dot movement of each dot before the error reflection due to thelanding interference calculated by the first dot-movement-amountcalculation unit 534A is referred to as before-error-reflection movementamount information 554A. The first dot-movement-amount calculation unit534A corresponds to one example of “first movement amount calculationmeans”. The before-error-reflection movement amount information 554Aacquired from the first dot-movement-amount calculation unit 534Acorresponds to one example of “first movement amount information.

The second dot-movement-amount calculation unit 534B calculates themovement direction and the movement amount of the dot movement of eachdot due to the landing interference based on the information of thecontact direction and the contact amount which is theafter-error-reflection contact state information 553B acquired from thesecond halftone image analysis unit 532B. The information indicating themovement direction and the movement amount of the dot movement of eachdot after the error reflection due to the landing interferencecalculated by the second dot-movement-amount calculation unit 534B isreferred to as after-error-reflection movement amount information 554B.The second dot-movement-amount calculation unit 534B corresponds to oneexample of “second movement amount calculation means. Theafter-error-reflection movement amount information 554B acquired fromthe second dot-movement-amount calculation unit 534B corresponds to oneexample of “second movement amount information”.

The process of step S611 of FIG. 74 is performed by the first halftoneimage analysis unit 532A and the first dot-movement-amount calculationunit 534A. The process of step S612 of FIG. 74 is performed by combiningthe error reflection processing unit 546, the second halftone imageanalysis unit 532B and the second dot-movement-amount calculation unit534B.

The movement-amount-change calculation unit 535 calculates the change ofthe movement direction and the movement amount of the dot movement dueto the landing interference after the error reflection based on thebefore-error-reflection movement amount information 554A and theafter-error-reflection movement amount information 554B. The process ofstep S613 of FIG. 74 is performed by the movement-amount-changecalculation unit 535.

The landing-interference-influence evaluation unit 536 calculateslanding interference evaluation values for quantitatively evaluating thechange of the influence of the dot movement due to the landinginterference before and after the error is reflected from theinformation indicating the changes of the movement direction and themovement amount acquired by the movement-amount-change calculation unit535. The landing-interference-influence evaluation unit 536 of thepresent example calculates the summation of the changes of the movementdirection and the movement amount described in step S614 of FIG. 74. Thelanding-interference-influence evaluation unit 536 corresponds to oneexample of “landing-interference-influence evaluation means”. The stepof causing the landing-interference-influence evaluation unit 536 tocalculate the landing interference evaluation value corresponds to oneexample of a “landing interference evaluation step”.

The reference value storage unit 538 is storage means for storinginformation of the specified reference value described in step S615 ofFIG. 74. The landing-interference-influence evaluation unit 536 comparesthe summation of the changes of the movement direction and the movementamount as the calculated landing interference evaluation values with thespecified reference value, and determines the degree of influence of thedot movement due to the landing interference.

The halftone process generation unit 58 generates the halftoneprocessing rule in cooperation with the landing-interference-influenceevaluation unit 536.

The process of step S615 of FIG. 74 is performed by thelanding-interference-influence evaluation unit 536 and the halftoneprocess generation unit 58.

In such a configuration, the halftone process generation unit 58 (seeFIG. 76) corresponds to one example of “signal processing means”, andthe step of causing the halftone process generation unit 58 to generatethe halftone parameter corresponds to one example of a “signalprocessing step”.

In addition to the configuration described in FIG. 76, the imageprocessing device 20 of FIG. 76 may have the same configuration as thatof the image quality evaluation processing unit 74 or thehalftone-selection-chart generation unit 76 described in FIG. 3.

<Case of Error Diffusion Method>

The flowchart of FIG. 64 may be applied to the generation of thehalftone parameter of the error diffusion method. Similarly to theexample described in FIG. 10, the flowchart of FIG. 64 is repeated forall the applied gradation sections, and thus, a diffusion coefficient ofthe error diffusion matrix of each applied gradation section isdetermined.

That is, the average value of the evaluation values for each gradationis used as an image quality evaluation value by temporarily setting thediffusion coefficient of the error diffusion matrix applied to a certaingradation section for the gradation section (step S501 of FIG. 64),performing the halftone process on the input image (a uniform image of asingle gradation) having each gradation in the gradation section (stepS502 of FIG. 64) and evaluating the image quality of the halftone image(step S503). The image quality evaluation (step S503) is performedsimilarly to the case of the dither method.

The evaluation (step S504) of the landing interference influence and thehalftone parameter update determining and updating process (step S505)are performed similarly to those in the dither method.

<Case where Void-and-Cluster Method is Applied to Dither Method>

FIG. 77 is a flowchart showing an example of the more detailedprocessing content of step S523 and step S524 of FIG. 69. In theflowchart of FIG. 77, the same or similar steps as or to the steps ofthe flowchart described in FIG. 74 will be assigned the same stepnumbers, and the description thereof will be omitted. The flowchart ofFIG. 77 includes the process of step S616 instead of step S615 of theflowchart described in FIG. 77.

Step S611 to step S614 of FIG. 77 correspond to step S523 of FIG. 69,and step S616 of FIG. 77 corresponds to the process of step S524 of FIG.69.

In step S616 of FIG. 77, the threshold values are set to pixels of whichthe summation of the changes of the contact state is equal to or lessthan the specified reference value and which are the minimum-energypixels (that is, void pixels) among the pixels of the halftone image inwhich the dots are not set, and the dots are set to the void pixels ofthe halftone image.

The flowchart shown in FIG. 77 is the process in a direction in whichthe threshold values are increased from the initial image, but a methodin which the threshold values (that is, gradation values) are decreasedfrom the initial image also follows the known void-and-cluster method.That is, a process of updating the halftone image by regarding themaximum-energy pixels among the pixels to which the dots are set ascluster pixels in which the dots are dense in the energy image acquiredby applying the filter to the halftone image, setting the thresholdvalues to the pixels and excluding the dots of the pixels issequentially repeated.

<Case where Halftone Process Using Direct Binary Research Method isPerformed>

FIG. 78 is a flowchart showing an example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71. Step S641 tostep S644 of FIG. 78 correspond to the process of step S534 of FIG. 71,and step S645 of FIG. 78 corresponds to the process of step S535 of FIG.71.

In step S641 of FIG. 78, the movement direction and the movement amountdue to the landing interference are calculated based on the contactdirection and the contact amount of each dot with the surrounding dotare calculated before the dot replacement and after the dot replacement.

Subsequently, the movement direction and the movement amount of each dotdue to the landing interference in the dot arrangement on which at leastone error of the dot diameter, the dot shape, the dot forming positionshift or the non-jetting are calculated before the dot replacement andafter the dot replacement is reflected (step S642 of FIG. 78).

The changes of the movement direction and the movement amount before andafter the error reflection are calculated before the dot replacement andafter the dot replacement (step S643).

The summation of the changes of the movement direction and the movementamount before and after the error reflection is calculated before thedot replacement and after the dot replacement is reflected (step S644).The method of calculating the changes of the movement direction and themovement amount before and after the error reflection is the same asstep S611 to step S614 of FIG. 77 and the example described in FIGS. 66,67 and 75.

Among the summations of the changes of the movement direction and themovement amount acquired in step S644 of FIG. 78, the summation of thechange of the movement direction and the movement amount after the errorreflection before the dot replacement is described as “Summation C₁”,and the summation of the change of the movement direction and themovement amount after the error reflection after the dot replacement isdescribed as “Summation C₂”

The process proceeds to step S645 after step S644 of FIG. 78. Step S645includes a determining process of determining whether or not to updatethe halftone image, and an updating process based on the determiningresult. In step S645, a process of comparing the summations of themovement directions and the movement amounts calculated in step S644with the specified reference value and updating the halftone parameterin a case where the summations of the movement directions and themovement amounts are equal to or less than the specified reference valueand the image quality evaluation value are enhanced before and after thedot replacement is performed.

That is, in step S645 of FIG. 78, in a case where Summation C2 of thechanges of the movement direction and the movement amount before andafter the error reflection after the dot replacement is equal to or lessthan the specified reference value and the image quality evaluationvalue acquired in step S533 of FIG. 71 is enhanced before and after thedot replacement, the process of updating the halftone image isperformed.

In the present example, it is determined whether or not to update thehalftone image by combining the summation of the changes of the movementdirection and the movement amount acquired in step S644 of FIG. 78 withthe image quality evaluation value acquired in step S533 of FIG. 71.

The “halftone image being updated” means that the halftone image isupdated by adopting the dot arrangement state after the dot replacementin which the dot replacement is performed in step S532 of FIG. 71.

Through the halftone process shown in FIGS. 71 and 78, it is possible togenerate the halftone image in which the change of the movement amountof the dot due to the influence of the landing interference is lessbefore and after the error is reflected.

The “change of the movement amount of the dot being less” means that thechange of the influence of the dot movement is equal to or less than thechange represented by the specified reference value.

According to the configuration described in FIGS. 71 to 78, it ispossible to generate the halftone image such that the dot arrangementfalls in the allowable range represented by the specified referencevalue based on the comparing result of the process of comparingSummation A and Summation B of the movement amounts which are thelanding interference evaluation values with the specified referencevalue.

The halftone process described in FIGS. 71 and 78 may be performed bythe halftone processing unit 80 shown in FIG. 76. The halftone image 550which is the target of the landing interference influence evaluation inthis case is the dot image generated during the process performed by thehalftone processing unit 80, and is the initial image described in stepS531 of FIG. 71, the image after the dot replacement in step S532, orthe updated halftone image that is updated in step S535. The halftoneprocessing unit 80 (see FIG. 76) that performs the halftone processdescribed in FIGS. 71 and 78 performs the updating process on thehalftone image using the DBS method in cooperation with thelanding-interference-influence evaluation unit 536.

In such configuration, the halftone processing unit 80 (see FIG. 76)corresponds to one example of “signal processing means”, and the step ofcausing the halftone processing unit 80 to generate the halftone imagecorresponds to one example of a “signal processing step”.

The processing content performed by the image processing device 20according to the embodiment described in FIGS. 74 to 78 described abovemay be comprehended as an image processing method.

According to the embodiment described in FIGS. 74 to 78, it is possibleto perform the halftone design or the halftone process in which theimage quality deterioration is less (that is, there is the tolerance tothe error) even though the error is added.

Modification Example of Specific Example Described FIGS. 74 to 78Modification Example 8

It has been described in the description of FIGS. 74 to 78 that themovement amount of the dot movement due to the landing interference iscalculated based on the information indicating the contact direction andthe contact amount of each dot. However, as described in FIG. 73, themovement amount of the dot movement due to the landing interference istreated to be approximately proportional to the contact amount of thedot, and thus, it is possible to directly calculate the landinginterference evaluation value from the contact direction and the contactamount.

It is possible to calculate the “landing interference evaluation value”from the change of the summation of the vectors indicating the contactdirection and the contact amount with the surrounding dot even thoughthe calculation of the movement vector described in FIG. 66 is notperformed.

Accordingly, the “dot-movement-amount calculation unit 534” described inFIG. 76 may be omitted. From a different viewpoint, it is understoodthat the movement amount information indicating the movement directionand the movement amount of the dot movement due to the landinginterference includes the information of the “contact direction and thecontact amount”. For example, the movement amount information items(554A and 554B) generated by the dot-movement-amount calculation unit534 are information items (553A and 553B) indicating the contactdirection and the contact amount.

Modification Example 9

The updating reference of the halftone parameter of step S505 of FIG. 64or the updating reference of the halftone image of step S524 of FIG. 69or the step S535 of FIG. 71 is not limited to the updating referenceshown in step S615 of FIG. 74, step S616 of FIG. 77 or step S645 of FIG.78, and various updating references may be determined.

For example, the updating reference may be a “case where the imagequality evaluation value or the energy is equal to or less than apredetermined reference value for a determination reference and thelanding interference movement amount summation is enhanced” or a “casewhere a weighted sum of the image quality evaluation value or the energyand the landing interference movement amount summation is enhanced”.

The “summation of the changes of the landing interference movementamount” is one example of a “landing interference evaluation value”.

The “case where the landing interference movement amount summation isenhanced” means that an increase/decrease tendency indicating whetherthe values of the changes of the landing interference movement amountare increased or decreased is comprehended, and it is determined thatthe “summation of the changes of the landing interference movementamount is enhanced” in a case where the summation of the changes of thelanding interference movement amount is decreased. When it is determinedwhether or not the summation of the changes of the landing interferencemovement amount is enhanced, since it is comprehended whether thesummation of the changes of the landing interference movement amount isincreased or decreased by comparing the values of the summations of thechanges of the landing interference movement amount calculated fromdifferent dot arrangements, a comparison process of comparing thesummation of the changes of the landing interference movement amount isincluded. The determining result of whether or not the summation of thechanges of the landing interference movement amount is enhanced is basedon the “comparing result” of the comparison process.

The “weighted sum of the image quality evaluation value or the energyand the summation of the changes of the landing interference movementamount” corresponds to one example of an “evaluation value” generatedbased on the “landing interference evaluation value”.

Modification Example 10

In a case where the predetermined error (hereinafter, referred to as anerror other than the non-jetting.) is reflected on the dot arrangementof the halftone image, since the landing interference movement amount ofthe dot group on which the error is reflected is greatly changed unlikethe case where the error is not reflected in most cases, the change ofthe landing interference movement amount of only the dot group on whichthe error is reflected may be evaluated. That is, the example of FIGS.66 and 67, the summation of the changes of the landing interferencemovement amount of only Dot 2 and Dot 5 on which the error of the dotforming position shift is reflected may be calculated.

In a case where the change of the landing interference movement amountafter the error reflection is estimated, the present example is notlimited to the aspect in which all the dots included in the dot imageare used as the targets, and some dots of all the dots included in thedot image may be used as the targets like an aspect in which only thedot group to which the error is added is used as the target.

Modification Example 11

In a case where the dot forming position shift is reflected as thepredetermined error, since the landing interference movement amount isgreatly changed in a direction parallel to the direction to which theerror is added, the change of the landing interference movement amountin only the direction parallel to the direction to which the error isadded may be evaluated. In this case, for only the dots in contact inthe direction to which the error is added, that is, only the dotsincluding the dot movement in only the movement direction parallel tothe direction to which the error is added, the summation of the changesof the landing interference movement amount may be calculated, or thesummation of the changes of the landing interference movement amountprojected in a line in the direction parallel to the direction to whichthe error is added may be calculated.

In the example shown in FIG. 67, the dots in contact in the direction towhich the error is added, that is, the dots including the dot movementin only the movement direction parallel to the direction to which theerror is added are Dot 1, Dot 2 and Dot 3. Accordingly, as the summationof the changes of the landing interference movement amount, thesummation of the changes of the movement amounts of the dot movement ofDot 1, Dot 2 and Dot 3 due to the landing interference may becalculated.

Modification Example 12

In both the single path type ink jet printing device and the serial typeink jet printing device, in a case where the predetermined error isadded, the dot movement in the direction perpendicular to the scanningdirection on the paper greatly contributes to the occurrence of thestreak.

Accordingly, in a case where the influence of the landing interferencein a state in which the predetermined error is added is evaluated, thechange of the movement amount of the dot movement in only the directionperpendicular to the scanning direction may be evaluated. In this case,for only the dots in contact in the direction perpendicular to thescanning direction, that is, only the dots including the movement inonly the direction perpendicular to the scanning direction, thesummation of the changes of the landing interference movement amount maybe calculated, or the summation of the changes of the landinginterference movement amount projected in a line in the directionperpendicular to the scanning direction may be calculated.

[Example of Halftone Design or Halftone Process in which Change of DotContact State after Error Reflection is Less]

In FIGS. 74 to 78, the example of the halftone design or the halftoneprocess in which the changes of the movement direction and the movementamount of the dot movement due to the landing interference after theerror reflection are less has been described.

Hereinafter, another embodiment capable of acquiring the same effect asthat of the embodiment described in FIGS. 74 to 78 will be described. Inthe embodiment to be mentioned below, the halftone design or thehalftone process is performed such that the change of the contact stateof the dot after the error reflection is less without calculating themovement direction or the movement amount of the dot due to the landinginterference. There is an advantage that the influence of the landinginterference can be simply evaluated from only the changes of thecontact state of the dot before and after the error is added withoutperforming the process of calculating the movement direction and themovement amount of the dot due to the landing interference.

Specifically, the “change of the contact state” mentioned herein may berepresented by the number of dots exhibiting any one state change of afirst state change in which a state in which a dot is in contact withanother dot is changed to a state in which a dot is not in contact withanother dot and a second state change in which a state in which a dot isbit in contact with another dot is changed to a state in which a dot isin contact with another dot, or both the state changes of the firststate change and the second state change.

The first state change which is the case where the state in which thedots are in contact is changed to the state in which the dots are not incontact is described as “contact→non-contact”. The second state changewhich is the case where the state in which the dots are not in contactis changed to the state in which the dots are in contact is described as“non-contact→contact”. It is possible to quantitatively evaluate thechange of the contact state by any one of the number of dots of“contact→non-contact” and the number of dots of “non-contact→contact” orthe number of dots of both states.

FIG. 79 is a flowchart capable of being applied instead of the flowchartof FIG. 74. FIG. 79 is a flowchart showing another example of the moredetailed processing contents of step S504 and step S505 of FIG. 64. StepS661 to step S664 of FIG. 79 correspond to the process of step S504 ofFIG. 64, and step S665 of FIG. 79 corresponds to the process of stepS505 of FIG. 64.

As shown in FIG. 79, the contact state of each dot of the plurality ofdots included in the halftone image with the surrounding dot isinitially comprehended (step S661). Information indicating the contactstate of the dot before the error reflection is acquired by step S661.The information indicating the contact state acquired in step S661 isinformation indicating whether or not each dot is in contact withanother dot, and corresponds to one example of “first information”.

Subsequently, the contact state of each dot with the surrounding dot ina case where at least one error of the dot diameter, the dot shape, thedot forming position shift or the non-jetting is reflected iscomprehended (step S662). Information indicating the contact state ofthe dot after the error reflection is acquired by step S662. Theinformation indicating the contact state acquired in step S662 isinformation indicating whether or not each dot is in contact withanother dot, and corresponds to one example of “second information”.

Subsequently, the change of the contact state with the surrounding dotafter the error reflection is evaluated from the information indicatingthe contact state of the dot before the error reflection acquired bystep S661 and the information indicating the contact state of the dotafter the error reflection acquired in step S662 (step S663).

In the example of FIGS. 66 and 67, the “change of the contact state” isdescribed. For example, the state change of Dot 5 and Dot 6 is“contact→non-contact”. In this case, a total of two state changes of onestate change of Dot 5 of interest and one state change of Dot 6 ofinterest may be regarded as being “contact→non-contact”, or the statechange of a group of Dot 5 and Dot 6 may be regarded as being“contact→non-contact”. The number of groups treated in the latter ishalf the number of dots treated in the former. The evaluation of thechange of the contact state by the number of dots of which the contactstate is changed includes the evaluation of the change of the contactstate by the number of dot groups of which the contact state is changed.

FIGS. 80A and 80B are explanatory diagrams showing another examplerelated to the change of the contact state. FIG. 80A shows an example ofthe dot image before the error reflection, and FIG. 80B shows an exampleof the dot image after the error reflection. Similarly to FIG. 67, inFIG. 80B, the error of the dot forming position shift is added to Dot 5.

As shown in FIG. 80A, another one Dot A in addition to Dot 6 is incontact with Dot 5 in the dot image before the error reflection. Asshown in FIG. 80B, since Dot 5 is moved in the dot image after the errorreflection, it is considered that the state change of Dot A in additionto Dot 6 is “contact→non-contact”. As for the change of the contactstate in this case, a total of 4 state changes of two state changes ofDot 5 of interest, one state change of Dot A of interest and one statechange of Dot 6 of interest may be regarded as being“contact→non-contact”, or the state change of a total of two groups ofone group of Dot 5 and Dot 6 and one group of Dot 5 and Dot A may beregarded as being “contact→non-contact”.

FIGS. 81A and 81B are explanatory diagrams showing another examplerelated to the change of the contact state. FIG. 81A shows an example ofthe dot image before the error reflection, and FIG. 81B shows an exampleof the dot image after the error reflection. Similarly to FIG. 67, inFIG. 81B, the error of the dot forming position shift is added to Dot 5.

As shown in FIGS. 81A and 81B, Dot 5 and Dot 6 before and after theerror reflection exhibit the state change of “contact→non-contact”, andDot 5 and Dot A exhibit the state change of “non-contact→contact”. Inthis case, since one “contact→non-contact” state change and one“non-contact→contact” state change of Dot 5 of interest, one“non-contact→contact” state change of Dot A of interest, and one“contact→non-contact” state change of Dot 6 of interest, a total of two“contact→non-contact” state changes and two “non-contact→contact” statechanges may be regarded as a whole. Alternatively, the“contact→non-contact” state change of a group of Dots 5 and 6 and the“non-contact→contact” state change of a group of Dots 5 and A may beregarded.

In step S663 of FIG. 79, the change of the contact state of the dotbefore and after the error reflection is evaluated by theabove-described method.

Subsequently, the summation of the changes of the contact state iscalculated (step S664). The summation calculated in step S664corresponds to one example of a “landing interference evaluation value”.The summation of the changes of the contact state is an evaluation valueacquired by adding the changes of the contact state of the dots withinthe dot image, and is an index indicating the degree of change of theinfluence of the dot movement due to the landing interference after theerror reflection. For example, the summation of the state changes of“non-contact→contact” and “contact→non-contact” is calculated as thelanding interference evaluation value.

The process proceeds to step S665 after step S664 of FIG. 79. Step S665includes a determining process of determining whether or not to updatethe halftone parameter, and an updating process based on the determiningresult. That is, in step S665, the process of comparing the summationsof the changes of the contact state with the specified reference valueand updating the halftone parameter in a case where the summations ofthe changes of the contact state are equal to or less than the specifiedreference value and the image quality evaluation value acquired in stepS503 of FIG. 64 is enhanced is performed.

The process of comparing the summation of the changes of the contactstate with the specified reference value corresponds to one example of a“comparison process”. The determination of whether or not the summationof the changes of the contact state is equal to or less than thespecified reference value is based on the “comparing result” of thecomparison process.

A case where the summation of the changes of the contact state is equalto or less than the specified reference value means that the change ofthe influence of the dot movement due to the landing interference isequal to or less than the change of the influence of the dot movementrepresented by the reference value.

In step S665 of FIG. 79, it is determined whether or not to update thehalftone parameter by combining the summation of the changes of thecontact state with the image quality evaluation value acquired in stepS503 of FIG. 64.

FIG. 82 is a block diagram of major parts for describing the function ofan image processing device according to a twelfth embodiment. In FIG.82, the same or similar elements as or to those of the configurationdescribed in FIG. 76 will be assigned the same reference numerals, andthe description thereof will be omitted.

The image processing device 20 according to the twelfth embodiment shownin FIG. 82 has the function of the process described in FIG. 79. Thatis, the image processing device 20 shown in FIG. 82 includes a halftoneimage analysis unit 532, a contact-state-change calculation unit 558, alanding-interference-influence evaluation unit 536, a reference valuestorage unit 538, a parameter acquisition unit 544, and an errorreflection processing unit 546. The image processing device 20 includesa halftone process generation unit 58, a halftone-processing-rulestorage unit 60, a halftone processing unit 80, and a data output unit66.

A first halftone image analysis unit 532A of the halftone image analysisunit 532 analyzes data of a halftone image 550 before the error isreflected by the error reflection processing unit 546, and generatesbefore-error-reflection contact state information 556A. Thebefore-error-reflection contact state information 556A is informationindicating whether each dot of the halftone image 550 is in contact oris not in contact with another dot. The before-error-reflection contactstate information 556A corresponds to one example of “first contactstate information”, and corresponds to one example of “firstinformation”.

A second halftone image analysis unit 532B of the halftone imageanalysis unit 532 analyzes data of a halftone image after the error isreflected on the halftone image 550 by the error reflection processingunit 546, and generates after-error-reflection contact state information556B. The after-error-reflection contact state information 556B isinformation indicating whether each dot of an after-error-reflectioncontact halftone image is in contact or is not in contact with anotherdot. The after-error-reflection contact state information 556Bcorresponds to one example of “second contact state information”, andcorresponds to one example of “second information”.

The process of step S661 of FIG. 79 is performed by the first halftoneimage analysis unit 532A of FIG. 82. The process of step S662 of FIG. 79is performed by combining the error reflection processing unit 546 withthe second halftone image analysis unit 532B.

The contact-state-change calculation unit 558 calculates a change of anafter-error-reflection contact state based on thebefore-error-reflection contact state information 556A and theafter-error-reflection contact state information 556B. The process ofstep S663 of FIG. 79 is performed by the contact-state-changecalculation unit 558.

The landing-interference-influence evaluation unit 536 calculates alanding interference evaluation value for quantitatively evaluating achange of the influence of the dot movement due to the landinginterference before and after the error is reflected from theinformation indicating the change of the contact state acquired by thecontact-state-change calculation unit 558. Thelanding-interference-influence evaluation unit 536 of the presentexample calculates the summation of the changes of the contact statedescribed in step S664 of FIG. 79.

The reference value storage unit 538 of FIG. 82 is storage means forstoring information of the specified reference value described in stepS665 of FIG. 79. The landing-interference-influence evaluation unit 536of FIG. 82 compares the summation of the changes of the contact state asthe calculated landing interference evaluation value with the specifiedreference value, and determines the degree of change of the influence ofthe dot movement due to the landing interference.

The process of step S665 of FIG. 79 is performed by thelanding-interference-influence evaluation unit 536 and the halftoneprocess generation unit 58 of FIG. 82.

<Case where Void-and-Cluster Method is Applied to Dither Method>

FIG. 83 is a flowchart capable of being applied instead of the flowchartof FIG. 77.

FIG. 83 is a flowchart showing an example of the more detailedprocessing contents of step S523 and step S524 of FIG. 69. In theflowchart of FIG. 83, the same or similar elements as or to the steps ofthe flowchart described in FIG. 79 will be assigned the same referencenumerals, and the description thereof will be omitted. The flowchart ofFIG. 83 includes the process of step S666 instead of step S665 of theflowchart described in FIG. 79.

Step S661 to step S664 of FIG. 83 correspond to the process of step S523of FIG. 69, and step S666 of FIG. 83 corresponds to the process of stepS524 of FIG. 69.

In step S666 of FIG. 83, the threshold values are set to pixels of whichthe summation of the changes of the contact state is equal to or lessthan the specified reference value and which are the minimum-energypixels (that is, void pixels) among the pixels of the halftone image inwhich the dots are not set, and the dots are set to the void pixels ofthe halftone image.

The flowchart shown in FIG. 83 is the process in a direction in whichthe threshold values are increased from the initial image, but a methodin which the threshold values (that is, gradation values) are decreasedfrom the initial image also follows the known void-and-cluster method.That is, a process of updating the halftone image by regarding themaximum-energy pixels among the pixels to which the dots are set ascluster pixels in which the dots are dense in the energy image acquiredby applying the filter to the halftone image, setting the thresholdvalues to the pixels and excluding the dots of the pixels issequentially repeated.

<Case where Halftone Process Using Direct Binary Research Method isPerformed>

FIG. 84 is a flowchart capable of being applied instead of the flowchartof FIG. 78. FIG. 84 is a flowchart showing an example of the moredetailed processing contents of step S534 and step S535 of FIG. 71. StepS671 to step S674 of FIG. 84 correspond to the process of step S534 ofFIG. 71, and step S675 of FIG. 84 corresponds to the process of stepS535 of FIG. 71.

In step S671 of FIG. 84, the contact state of each dot with thesurrounding dot is comprehended before the dot replacement and after thedot replacement. In step S671, information indicating the contact stateof the dot before the error reflection before and after the dotreplacement is acquired. The information indicating the contact state ofthe dot before dot replacement and before the error reflection acquiredin step S671 and the information indicating the contact state of the dotafter the dot replacement and before the error reflection correspond toone example of “first contact state information and correspond to oneexample of “first information”.

Subsequently, the contact state of each dot in the dot arrangement onwhich at least one error of the dot diameter, the dot shape, the dotforming position shift or the non-jetting is reflected with thesurrounding dot is comprehended before the dot replacement and after thedot replacement (step S672). In step S672, information indicating thecontact state of the dot after the error reflection before and after thedot replacement is acquired. The information indicating the contactstate of the dot before the dot replacement and after the errorreflection acquired in step S672 and the information indicating thecontact state of the dot after the dot replacement and after the errorreflection correspond to one example of “second contact stateinformation” and correspond to one example of “second information”.

Subsequently, the change of the contact state with the surrounding dotbefore and after the error reflection is evaluated before the dotreplacement and after the dot replacement (step S673). The method ofevaluating the change of the contact state is the same as the methoddescribed in step S663 of FIG. 79.

The summations of the changes of the contact state before and after theerror reflection are calculated before the dot replacement and after thedot replacement (step S674 of FIG. 84). The method of acquiring thesummation of the changes of the contact state is the same as the exampledescribed in step S664 of FIG. 79.

Among the summations of the changes of the contact state acquired instep S674 of FIG. 84, the summation of the changes of the contact statebefore the dot replacement is described as “Summation E₁”, and thesummation of the changes of the contact state after the dot replacementis described as “Summation E₂”.

The process proceeds to step S675 after step S674 of FIG. 84. Step S675includes a determining process of determining whether or not to updatethe halftone image, and an updating process based on the determiningresult. That is, in step S675, a process of comparing the summations ofthe changes of the contact state calculated in step S674 with thespecified reference value and updating the halftone image in a casewhere the summations of the changes of the contact state are equal to orless than the specified reference value and the image quality evaluationvalue is enhanced before and after the dot replacement is performed.

That is, in step S675 of FIG. 84, in a case where summation E₂ of thechanges of the contact state after the dot replacement is equal to orless than the specified reference value and the image quality evaluationvalue calculated in step S533 of FIG. 71 is enhanced before and afterthe dot replacement, the process of updating the halftone image isperformed.

In the present example, it is determined whether or not to update thehalftone image by combining the summations of the changes of the contactstate calculated in step S674 of FIG. 84 with the image qualityevaluation value calculated in step S533 of FIG. 71.

Through the halftone process shown in FIGS. 71 and 84, it is possible togenerate the halftone image in which the change of the dot contact statedue to the influence of the landing interference before and after theerror is reflected is less.

The “change of the dot contact state being less” means that the degreeof change of the dot contact state is equal to or less than the degreeof change represented by the specified reference numeral. That is, thechange of the dot contact state being less means that the change of theinfluence due to the dot movement is less.

The halftone process described in FIGS. 71 and 84 may be performed bythe halftone processing unit 80 shown in FIG. 82. The halftone image 550as the target of the landing interference influence evaluation in thiscase is the dot image generated during a process performed by thehalftone processing unit 80, and is the initial image described in stepS531 of FIG. 71, the image after dot replacement in step S532, or theupdated halftone image that is updated in step S535. The halftoneprocessing unit 80 (see FIG. 82) that performs the halftone processdescribed in FIGS. 71 and 84 performs the updating process on thehalftone image using the DBS method in cooperation with thelanding-interference-influence evaluation unit 536.

In such configuration, the halftone processing unit 80 (see FIG. 82)corresponds to one example of “signal processing means”, and the step ofcausing the halftone processing unit 80 to generate the halftone imagecorresponds to one example of a “signal processing step”.

According to the embodiment described in FIGS. 71 to 84, it is possibleto generate the halftone image such that the dot arrangement falls inthe allowable range represented by the specified reference value basedon the comparing result of the process of comparing the summation of thechanges of the contact stage as the landing interference evaluationvalue with the specified reference value.

The processing content performed by the image processing device 20according to the embodiment described in FIGS. 79 to 84 described abovemay be comprehended as an image processing method.

According to the embodiment described in FIGS. 79 to 84, it is possibleto perform the halftone design or the halftone process in which theimage quality deterioration is less (that is, there is the tolerance tothe error) even though the error is added based on only the change ofthe dot contact state without calculating the movement direction and themovement amount of the dot movement due to the landing interference.

Modification Example of Specific Example Described in FIGS. 79 to 84Modification Example 13

When the influence of the landing interference is evaluated, it has beendescribed in the above-described specific example that the summation ofthe state changes of “non-contact→contact” and “contact→non-contact” iscalculated as the landing interference evaluation value, and the methodof calculating the landing interference evaluation value is not limitedto this example. For example, the summation of the state changes of“non-contact→contact” and the summation of the state changes“contact→non-contact” may be respectively used as the landinginterference evaluation values. The summation of the state changes ofonly any one of “non-contact→contact” and “contact→non-contact” may beused as the landing interference evaluation value.

Modification Example 14

The updating reference of the halftone parameter of step S505 of FIG. 64or the updating reference of the halftone image of step S524 of FIG. 69or the step S535 of FIG. 71 is not limited to the updating referenceshown in step S665 of FIG. 79, step S666 of FIG. 83 or step S675 of FIG.84, and various updating references may be determined.

For example, the updating reference may be a “case where the imagequality evaluation value or the energy is equal to or less than apredetermined reference value for a determination reference and thesummation of the changes of the contact state is enhanced” or a “casewhere a weighted sum of the image quality evaluation value or the energyand the summation of the changes of the contact state is enhanced”.

The “summation of the changes of the contact state” is one example of a“landing interference evaluation value”. The “summation of the changesof the contact state” may be the summation of the state changes of“contact→non-contact”, may be a weighted summation of the summation ofthe state changes of “contact→non-contact” and the summation of thestate changes of “non-contact→contact”, or may be the summation of thestate changes of any one of “contact→non-contact” and“non-contact→contact”.

The “case where the summation of the changes of the contact state isenhanced” means that an increase/decrease tendency indicating whetherthe value of the summation of the changes of the contact state isincreased or decreased is comprehended, and it is determined that the“summation of the changes of the contact state is enhanced” in a casewhere the summation of the changes of the contact state is decreased.When it is determined whether or not the summation of the changes of thecontact state is enhanced, since it is comprehended whether thesummation of the changes of the contact state is increased or decreasedby comparing the value of the summation of the changes of the contactstate acquired from different dot arrangements, a comparison process ofcomparing the summation of the changes of the contact state is included.The determining result of whether or not the summation of the changes ofthe contact state is enhanced is based on the “comparing result” of thecomparison process.

The “weighted sum of the image quality evaluation value or the energyand the summation of the changes of the contact state” is a totalevaluation value acquired by adding the evaluation of the image qualityand the evaluation of the influence of the landing interference, andcorresponds to one example of an “evaluation value generated based onthe landing interference evaluation value”.

Modification Example 15

In a case where a predetermined error (hereinafter, an error other thanthe non-jetting is used.) is reflected on the dot arrangement of thehalftone image, since the contact state of the dot group on which theerror is reflected is greatly changed unlike a case where the error isnot reflected in most cases, the change of the contact state of only thedot group on which the error is reflected may be evaluated. That is, theexample of FIG. 67, the summation of the changes of the contact state ofonly Dot 2 and Dot 5 is reflected may be calculated as the summation ofthe changes of the contact state on which the error of the dot formingposition shift is reflected.

In a case where the change of the contact state of the dot before andafter the error reflection is calculated, the present example is notlimited to the aspect in which all the dots included in the dot imageare used as the targets, and some dots of all the dots included in thedot image may be used as targets like an aspect in which only the dotgroup to which the error is added is used as a target.

Modification Example 16

In a case where the dot forming position shift as the predeterminederror is reflected, since the contact state of the dot in a directionparallel to the direction to which the error is added is greatly changedin most cases, only the change of the contact state in only thedirection parallel to the direction to which the error is added may beevaluated. In this case, only any one of the state change of“contact→non-contact” in a direction parallel to the direction to whichthe error of the dot forming position shift is added and the statechange of “non-contact→contact” or both the state changes may beevaluated, or the landing interference evaluation value may becalculated.

Modification Example 17

As already described, in both the single path type and serial type inkjet printing devices, in a case where the predetermined error is added,the dot movement in the direction perpendicular to the scanningdirection on the paper greatly contributes the occurrence of the streak.Accordingly, only the change of the contact state of the dot in thedirection perpendicular to the scanning direction may be evaluated. Inthis case, “contact→non-contact” and/or “non-contact→contact” in thedirection perpendicular to the scanning direction is paid attention to,and only the number of dots exhibiting “contact→non-contact” and/or“non-contact→contact” in the direction perpendicular to the scanningdirection may be evaluated.

For example, in the example of FIGS. 81A and 81B, the direction to whichthe error due to the dot forming position shift is added is a direction(a horizontal direction in the drawings) parallel to the X direction,and the scanning direction is the Y direction (a vertical direction inthe drawing). In the example shown in FIGS. 81A and 81B, the “change ofthe contact state of the dot in the direction perpendicular to thescanning direction” is the state change of “non-contact→contact” of Dot5 and Dot A.

[Still Another Specific Example of Means for Applying Tolerance toLanding Interference]

Hereinafter, still another specific example of the configuration inwhich the halftone design or the halftone process of suppressing theimage quality deterioration due to the landing interference is realizedwill be described. Here, the processing content of the halftone designand the halftone process having favorable dispersibility of the dot foreach group (that is, on a per group basis) by estimating the movementdirection and the movement amount of the dot movement due to the landinginterference based on the contact direction and the contact amount ofeach dot with the surrounding dot and classifying the dots into groupsaccording to the movement direction and the movement amount will bedescribed. Even though the landing interference occurs, the halftoneimage in which the image quality deterioration due to the influencethereof is relatively less is acquired by performing the halftone designor the halftone process.

Three examples of an example of the process of generating the halftoneparameter in the dither method or the error diffusion method, an exampleof the process of generating the halftone parameter by thevoid-and-cluster with respect to the dither method, and an example ofthe halftone process in the direct binary search method will bedescribed by referring to FIGS. 10, 14 and 16 already described.

<Application Example to Process of Generating Halftone Parameter inDither Method or Error Diffusion Method>

FIG. 85 is a flowchart showing an example of the more detailedprocessing contents of step S504 and step S505 of FIG. 64.

Step S711 to step S713 of FIG. 85 correspond to step S504 of FIG. 64,and step S715 of FIG. 85 corresponds to the process of step S505 of FIG.64.

As shown in FIG. 85, the movement direction and the movement amount dueto the landing interference are initially calculated based on thecontact direction and the contact amount of each dot of the plurality ofdots included in the halftone image with the surrounding dot (stepS711). The method described in FIG. 66 may be applied to the method ofcalculating the movement direction and the movement amount due to thelanding interference. As described in FIG. 66, the movement vector ofeach dot of the halftone image with the surrounding dot due to thelanding interference, that is, the movement direction and the movementamount is calculated (step S711 of FIG. 85), and the dots are classifiedinto groups based on the movement direction and the movement amount(step S712). The detailedness of the movement direction and the movementamount classified into the groups does not matter. For example, themovement directions are classified into 8 groups of left, right, up,down, upper left, upper right, lower left, and lower right, and themovement amounts are classified into three groups of “no movement orminute-scale movement”, “medium-scale movement” and “large-scalemovement”. Thus, it is possible to perform the classification into atotal of 24 groups by the combinations of the movement directions andthe movement amounts. The “minute-scale movement”, “medium-scalemovement” and “large-scale movement” related to the movement amount arecategories acquired by dividing the degree of movement amount into 3steps. It is possible to appropriately set the value range of themovement amount for determining the categories of the minute-scalemovement, the medium-scale movement and the large-scale movement”.

In the example of FIG. 66, Dot 2 is classified as the group of “nomovement or minute-scale movement”. Dot 3 is classified as the group of“medium-scale movement to the left”, Dot 1 is classified as the group of“medium-scale movement to the right”, Dot 5 is classified as the groupof “medium-scale movement down”, Dot 6 is classified as the group of“medium-scale movement to the upper left”, and Dot 4 is classified asthe group of “medium-scale to the upper right”.

It has been described in FIG. 67 that the error of the dot formingposition shift is reflected on the dot image shown in FIG. 66. Asdescribed in FIG. 67, the movement vector of each dot of the halftoneimage in a state in which the predetermined error is added with thesurrounding dot due to the landing interference, that is, the movementdirection and the movement amount may be calculated.

Accordingly, a configuration in which the movement direction and themovement amount due to the landing interference are calculated based onthe contact direction and the contact amount of each dot of theafter-error-reflection halftone image in which at least one error of thedot diameter, the dot shape, the dot forming position shift or thenon-jetting is reflected and the group classifying process is performedbased on the acquired movement direction and movement amount may beadopted.

In the example shown in FIG. 67, in a case where the classification intoa total of 24 groups is performed by the combinations of the movementdirections of the dot movement due to the landing interference areclassified into 8 kinds of groups and the movement amounts areclassified into 3 kinds of groups, Dot 3 and Dot 6 are classified as thegroup of “no movement or minute-scale movement”. Dot 2 of FIG. 67 isclassified as the group of “medium-scale movement to the left”, Dot 1 isclassified as the group of “large-scale movement to the right”, Dot 4 isclassified as the group of “large-scale movement to the upper right”,and Dot 5 is classified as the group of “large-scale movement to thelower left”.

A configuration in which the group classifying process and theevaluation of the dispersibility of each group are performed in only acase where at least one error of the dot diameter, the dot shape, thedot forming position shift or the non-jetting is reflected may beadopted.

The dot group of each group classified in terms of the movementdirection and the movement amount of the dot movement due to the landinginterference in a case where at least one error of the dot diameter, thedot shape, the dot forming position shift or the non-jetting isreflected has favorable dispersibility, and thus, it is possible toperform the halftone design or the halftone process in which the imagequality is favorable in a state in which the error is added or the imagequality deterioration is less even though the error is added (that is,there is the tolerance to the error).

The “favorable dispersibility” refers to a state in which the distancebetween adjacent dots is uniform or the density is uniform, and in thepresent example, root mean square (RMs) granularity is calculated as adispersibility evaluation value as an index for evaluationdispersibility by applying a visual transfer function (VTF) which is afunction representing human visual sensitivity to the dot data.

The RMS granularity is the root mean square of density variations, andis expressed by the following expression.SQRT(Σ(Di−D_ave)²/(N−1))

Here, SQRT( ) represents a function for acquiring the square root ofvalues designated by parameters described in parentheses. Di representsthe density of each pixel. D_ave represents a density average. Nrepresents the number of pixels. Σ(Di−D_ave)² represents the summationof all pixels of (Di−D_ave)².

A state in which the value of the RMS granularity is small refers to“favorable dispersibility”.

The process proceeds to step S713 after the group classifying process ofStep S712 of FIG. 38. In step S713, a process of evaluating thedispersibility of dots belonging to each group of the classified groupsis performed. As mentioned above, in the present example, the RMSgranularity is calculated as the dispersibility evaluation value as theindex for evaluating the dispersibility by applying the visual transferfunction to the dot data.

It may be considered that the dispersibility evaluation value is oneexample of the landing interference evaluation value for evaluating theinfluence of the dot movement due to the landing interference. Thedegree of influence of the landing interference is quantified as a valueby the dispersibility evaluation value.

The process proceeds to step S715 after step S713 of FIG. 85. Step S715includes a determining process of determining whether or not to updatethe halftone parameter, and an updating process based on the determiningresult.

In step S715, a process of comparing the dispersibility evaluation valueof each group acquired for each group with the specified reference valueand updating the halftone parameter in a case where the dispersibilityevaluation value of each group is equal to or less than the specifiedreference value and the image quality evaluation value acquired in stepS503 of FIG. 64 is enhanced is performed. The process of comparing thedispersibility evaluation value of each group with the specifiedreference value corresponds to one example of a “comparison process”.The determination of whether or not the dispersibility evaluation valueof each group is equal to or less than the specified reference value isbased on the “comparing result” of the comparison process.

The specified reference value mentioned herein is a value thatdetermines an allowable upper limit of the influence of the dot movementdue to the landing interference, and is previously determined in a rangein which the image quality deterioration due to the landing interferencefalls in an allowable level. A case where the dispersibility evaluationvalue is equal to or less than the specified reference value means thatfavorable dispersibility equal to or greater than the dispersibilityrepresented by the reference value is acquired for each group. That is,a case where the dispersibility of each group is equal to or less thanthe specified reference value means that the influence of the dotmovement due to the landing interference is equal to or less than theinfluence of the dot movement represented by the reference value.

In step S715, it is determined whether or not to update the halftoneparameter by combining the dispersibility of each group with the imagequality evaluation value acquired in step S503 of FIG. 64.

The “halftone parameter being updated” means that the halftone parameteris updated by adopting the halftone parameter temporarily set in stepS501 of FIG. 64.

According to the configuration described in FIGS. 64 and 85, it ispossible to generate the halftone parameter such that the dotarrangement falls in the allowable range represented by the specifiedreference value based on the comparing result of the process ofcomparing the dispersibility evaluation value with the specifiedreference value.

That is, according to the process described in FIGS. 64 and 85, it ispossible to generate the halftone processing rule in which thedispersibility of each dot group which is moved in the same movementdirection by the same movement amount is favorable and the image qualitydeterioration due to the landing interference is less, that is, whichhas the tolerance to the landing interference even though the dotmovement due to the landing interference occurs.

As the “same movement direction”, the range of the movement directionsclassified as the same group is comprehensively described as the “samemovement direction”. The range of the movement direction correspondingto the “same movement direction” is different depending on thedetailedness of the classification when the group classifying process isperformed.

As the “same movement amount”, the range of the movement amountsclassified as the same group is comprehensively described as the “samemovement group”. The range of the movement amount corresponding to the“same movement amount” is different depending on the detailedness of theclassification when the group classifying process is performed.

FIG. 86 is a block diagram of major parts for describing the function ofan image processing device according to a thirteenth embodiment. In FIG.86, the same or similar elements as or to those of the configurationdescribed in FIG. 3 will be assigned the same reference numerals, andthe description thereof will be omitted.

An image processing device 20 according to the thirteenth embodimentshown in FIG. 86 has a function of performing the processes described inFIGS. 64 and 85. That is, the image processing device 20 shown in FIG.86 includes a halftone image analysis unit 532, a dot-movement-amountcalculation unit 534, a group classification processing unit 537, areference value storage unit 538, a dispersibility-evaluation-valuecalculation unit 539, a halftone process generation unit 58, ahalftone-processing-rule storage unit 60, a halftone processing unit 80,and a data output unit 66.

The halftone image analysis unit 532 analyzes data of a halftone image550, and generates information of the contact direction and the contactamount of each dot of the halftone image 550 with the surrounding dotwhich is another dot. The halftone image analysis unit 532 correspondsto one example of “analysis means”. The process of causing the halftoneimage analysis unit 532 to analyze the contact state of the dot and togenerate the information of the contact direction and the contact amountindicating the contact state corresponds to one example of an “analysisprocess”. The processing function of the halftone image analysis unit532 corresponds to one example of an “analysis function”.

The halftone image 550 is the dot image generated during the process ofcausing the halftone process generation unit 58 to determine thehalftone parameter. The dot image refers to an image indicating a dotarrangement form. The halftone image 550 is generated in the process ofstep S502 of FIG. 64.

The dot-movement-amount calculation unit 534 calculates a movementdirection and a movement amount of the dot movement of each dot due tothe landing interference based on the information of the contactdirection and contact amount of each dot acquired from the halftoneimage analysis unit 532 with the surrounding dot. Thedot-movement-amount calculation unit 534 corresponds to one example of“movement amount calculation means”. The process of causing thedot-movement-amount calculation unit 534 to calculate the movementamount of the dot movement corresponds to one example of a movementamount calculation step. The processing function of thedot-movement-amount calculation unit 534 corresponds to one example of amovement amount calculation function.

The group classification processing unit 537 performs a groupclassifying process of classifying the dots into one or a plurality ofgroups based on the information indicating the movement direction andthe movement amount calculated by the dot-movement-amount calculationunit 534. It is understood that since the information of the movementdirection and the movement amount acquired from the dot-movement-amountcalculation unit 534 is generated based on the information of thecontact direction and the contact amount acquired from the halftoneimage analysis unit 532, the group classification processing unit 537performs the group classifying process based on the information of thecontact direction and the contact amount acquired from the halftoneimage analysis unit 532. The group classification processing unit 537corresponds to one example of “group classification means”. The processof causing the group classification processing unit 537 to perform thegroup classifying process corresponds to one example of a “groupclassifying process”.

The dispersibility-evaluation-value calculation unit 539 calculates thedispersibility evaluation value for evaluating the dispersibility of thedot group for each group classified by the group classificationprocessing unit 537. The dispersibility-evaluation-value calculationunit 539 may further have a function of generating another evaluationvalue based on the dispersibility evaluation value of each group. As theevaluation value generated based on the dispersibility evaluation valueof each group, there may be a weighted sum of the dispersibilityevaluation values of the respective groups, and a weighted sum of thedispersibility evaluation value of each group and the image qualityevaluation value generated in step S503 of FIG. 37. Thedispersibility-evaluation-value calculation unit 539 corresponds to oneexample of “dispersibility-evaluation-value calculation means”. Theprocess of causing the dispersibility-evaluation-value calculation unit539 to calculate the dispersibility evaluation value corresponds to oneexample of a “dispersibility-evaluation-value calculation step”.

The reference value storage unit 538 is storage means for storing theinformation of the specified reference value described in step S715 ofFIG. 85. The dispersibility-evaluation-value calculation unit 539compares the calculated dispersibility evaluation value or theevaluation value generated based on the dispersibility evaluation valuewith the specified reference value, and determines the degree ofinfluence of the dot movement due to the landing interference. Thedispersibility-evaluation-value calculation unit 539 has a function ofthe landing-interference-influence evaluation means for evaluating theinfluence of the landing interference.

The halftone process generation unit 58 generates the halftoneprocessing rule in cooperation with the dispersibility-evaluation-valuecalculation unit 539.

The process of step S711 of FIG. 85 is performed by the halftone imageanalysis unit 532 and the dot-movement-amount calculation unit 534. Theprocess of step S712 of FIG. 85 is performed by the group classificationprocessing unit 537. The process of step S713 of FIG. 85 is performed bythe dispersibility-evaluation-value calculation unit 539. The process ofstep S715 of FIG. 85 is performed by the dispersibility-evaluation-valuecalculation unit 539 and the halftone process generation unit 58.

In such a configuration, the halftone process generation unit 58 (seeFIG. 86) corresponds to one example of “signal processing means”, andthe process of causing the halftone process generation unit 58 togenerate the halftone parameter corresponds to one example of a “signalprocessing step”. The processing function of the halftone processgeneration unit 58 corresponds to one example of a “signal processingfunction”.

In addition to the configuration described in FIG. 86, the imageprocessing device 20 of FIG. 86 may have the same configuration as thatof the image quality evaluation processing unit 74 or thehalftone-selection-chart generation unit 76 described in FIG. 3.

<Case of Error Diffusion Method>

The flowchart of FIG. 64 may be applied to the generation of thehalftone parameter of the error diffusion method. Similarly to theexample described in FIG. 10, a diffusion coefficient of an errordiffusion matrix of each applied gradation section is determined byrepeatedly performing the flowchart of FIG. 64 on all the appliedgradation sections.

That is, it is assumed that an average value of the respectiveevaluation values of each gradation is used as an image qualityevaluation value by temporarily setting a diffusion coefficient of theerror diffusion matrix applied to a certain gradation section for thegradation section (step S501 of FIG. 64), performing the halftoneprocess on the input image (a uniform image of a single gradation) ofeach gradation of the gradation section (step S502 of FIG. 64), andevaluating the image quality of the halftone image (step S503). Theimage quality evaluation (step S503) is performed similarly to that inthe dither method.

The evaluation (step S504) of the landing interference influence and thehalftone parameter update determining and updating process (step S505)are performed similarly to those in the dither method.

<Case where Void-and-Cluster Method is Applied to Dither Method>

FIG. 87 is a flowchart showing an example of the more detailedprocessing contents of step S523 and step S524 of FIG. 69. In theflowchart of FIG. 87, the same or similar steps as or to the steps ofthe flowchart described in FIG. 85 will be assigned the same stepnumbers, and the description thereof will be omitted. The flowchart ofFIG. 87 includes the process of step S716 instead of step S715 of theflowchart described in FIG. 85.

Step S711 to step S713 of FIG. 87 correspond to the process of step S523of FIG. 69, and step S716 of FIG. 87 corresponds to the process of stepS524 of FIG. 69.

In step S716 of FIG. 87, the threshold values are set to pixels of whichthe dispersibility evaluation values of the respective groups arerespectively equal to or less than the specified reference value andwhich are the minimum-energy pixels (that is, void pixels) among thepixels of the halftone image in which the dots are not set, and the dotsare set to the void pixels of the halftone image.

The flowchart shown in FIG. 87 is the process in a direction in whichthe threshold values are increased from the initial image, but a methodin which the threshold values (that is, gradation values) are decreasedfrom the initial image also follows the known void-and-cluster method.That is, a process of updating the halftone image by regarding themaximum-energy pixels among the pixels to which the dots are set ascluster pixels in which the dots are dense in the energy image acquiredby applying the filter to the halftone image, setting the thresholdvalues to the pixels and excluding the dots of the pixels issequentially repeated.

<Case where Halftone Process Using Direct Binary Search Method isPerformed>

FIG. 88 is a flowchart showing an example of the more detailedprocessing contents of step S534 and step S535 of FIG. 71. Step S741 tostep S744 of FIG. 88 correspond to the process of step S534 of FIG. 71,and step S745 of FIG. 88 corresponds to the process of step S535 of FIG.71.

In step S741 of FIG. 88, the movement direction and the movement amountdue to the landing interference are calculated based on the contactdirection and the contact amount of each dot with the surrounding dotbefore the dot replacement and after the dot replacement.

The dots are classified into groups based on the movement direction andthe movement amount before the dot replacement and after the dotreplacement (step S743). The method of calculating the movement amountof each dot due to the landing interference and the group classifyingmethod are the same as step S711 and step S712 of FIG. 85 and theexample described in FIG. 66.

Subsequently, the dispersibility of each group is evaluated (step S744of FIG. 88). The dispersibility evaluation value of each group of thedot image before the dot replacement and the dispersibility evaluationvalue of each group of the dot image after the dot replacement areacquired.

The process proceeds to step S745 after step S744. Step S745 includes adetermining process of determining whether or not to update the halftoneimage, and an updating process based on the determining result. That is,in step S745, a process of comparing the dispersibility evaluation valueof each group of the dot image after the dot replacement calculatedthrough the dot replacement with the specified reference value andupdating the halftone image in a case where the dispersibilityevaluation value of each group is equal to or less than the specifiedreference value and the image quality evaluation value acquired in stepS533 of FIG. 71 is enhanced before and after the dot replacement isperformed.

That is, in step S745 of FIG. 88, it is determined whether or not toupdate the halftone image by combining the dispersibility evaluationvalue of each group after the dot replacement with the image qualityevaluation value acquired in step S533 of FIG. 71.

The “halftone parameter being updated” means that the halftone image isupdated by adopting the dot arrangement state after the dot replacementon which the dot replacement is performed in step S532 of FIG. 71.

According to the configuration described in FIGS. 71 and 88, it ispossible to generate the halftone processing rule in which thedispersibility of each dot group which is moved in the same movementdirection by the same movement amount is favorable and the image qualitydeterioration due to the landing interference is less, that is, whichhas the tolerance to the landing interference even though the dotmovement due to the landing interference occurs. The “favorabledispersibility” means that the dot group has favorable dispersibilitywhich is equal to or greater than a reference of the dispersibilityrepresented by the specified reference value.

According to the configuration described in FIGS. 71 and 88, it ispossible to generate the halftone image such that the dot arrangementfalls in an allowable range indicated by the specified reference valuebased on the comparing result of the process of comparing thedispersibility evaluation value with the specified reference value bycalculating the dispersibility evaluation value of each group for eachgroup of the dot groups in which the movement direction and the movementamount of the dot movement due to the landing interference are the same.

The halftone process described in FIGS. 71 and 88 may be performed bythe halftone processing unit 80 shown in FIG. 86. The halftone image 550as a target on which the landing interference influence evaluation inthis case is performed is the dot image generated during the processperformed by the halftone processing unit 80, and the initial imagedescribed in step S531 of FIG. 71, the image after the dot replacementin step S532, or the updated halftone image that is updated in stepS535. The halftone processing unit 80 (see FIG. 86) that performs thehalftone process described in FIGS. 71 and 88 performs the updatingprocess on the halftone image using the DBS method in cooperation withthe dispersibility-evaluation-value calculation unit 539.

In such a configuration, the halftone processing unit 80 (see FIG. 86)corresponds to one example of “signal processing means”, and the processof causing the halftone processing unit 80 to generate the halftoneimage corresponds to one example of a “signal processing step”. Theprocessing function of the halftone processing unit 80 corresponds toone example of a “signal processing function”.

[Example of Halftone Design and/or Halftone Process Having ErrorTolerance]

Hereinafter, the configuration examples in which the image qualitydeterioration due to the landing interference in a case where there isat least one error of the dot diameter, the dot shape, the dot formingposition shift or the non-jetting is suppressed will be described.

FIG. 89 is a block diagram of major parts for describing a function ofan image processing device according to a fourteenth embodiment. In FIG.89, the same or similar elements as or to those of the configurationdescribed in FIGS. 3 and 86 will be assigned the same referencenumerals, and the description thereof will be omitted.

An image processing device 20 according to the fourteenth embodimentdescribed in FIG. 89 includes a parameter acquisition unit 544, and anerror reflection processing unit 546 in addition to the configurationdescribed in FIG. 86.

The parameter acquisition unit 544 is means for acquiring the parameterindicating at least one error of the dot diameter, the dot shape, thedot forming position shift or the non-jetting. In the example describedin FIG. 67, the parameter indicating the dot forming position shiftdirection and the dot forming position shift amount related to the errorof the dot forming position is acquired. The parameter acquisition unit544 may be a user interface, may be a communication interface or a datareception terminal that receives parameter information retained in anexternal storage medium or within the device, or may be an appropriatecombination thereof.

The error reflection processing unit 546 performs a process ofgenerating the arrangement of dots on which the error represented by theparameter acquired from the parameter acquisition unit 544 is reflected.The error reflection processing unit 546 reflects the error representedby the parameter acquired from the parameter acquisition unit 544 on thedata of the halftone image 550, and generates a dot image indicating adot arrangement state after the error reflection. In the exampledescribed in FIG. 67, the error reflection processing unit 546 generatesdata of the dot arrangement to which the error due to the dot formingposition shift is added. The error reflection processing unit 546corresponds to one example of “error reflection processing means”. Theprocess of causing the error reflection processing unit 546 to add theerror on the dot of the halftone image 550 and generate the dotarrangement on which the error is reflected corresponds to one exampleof an error reflection processing step.

The halftone image analysis unit 532 may perform analysis the contactdirection and the contact amount on an after-error-reflection halftoneimage after the error is added to the halftone image 550 by the errorreflection processing unit 546.

The halftone image analysis unit 532 may perform analysis the contactdirection and the contact amount on the halftone image 550 before theerror is added by the error reflection processing unit 546 and anafter-error-reflection halftone image acquired by adding the error tothe halftone image 550 by means of the error reflection processing unit546.

The halftone image 550 before the error is added (that is, the casewhere the non-reflection of the error is performed) is a dot image.

In such a configuration shown in FIG. 89, the movement direction and themovement amount of the dot movement due to the landing interference maybe calculated for an after-error-reflection-dot acquired by reflectingat least one error of the dot diameter, the dot shape, the dot formingposition shift or the non-jetting on the halftone image 550, and thegroup classification process may be performed depending on the movementdirection and the movement amount. The specific group classificationmethod is as described in FIG. 67.

Although the flowchart of the processes performed by the imageprocessing device 20 according to the fourteenth embodiment shown inFIG. 89 is not shown, the movement direction and the movement amount arecalculated based on the contact direction and the contact amount of eachdot in a case where at least one error of the dot diameter, the dotshape, the dot forming position shift or the non-jetting is reflectedinstead of the process of step S711 of FIG. 85 or 87 with thesurrounding dot. Thereafter, similarly to the flowchart of FIG. 85 or87, the group classification process is performed based on the movementdirection and the movement amount in a case where the error is reflected(step S712), and the evaluation of the dispersibility of each group isperformed (step S713).

As for the halftone process using the direct binary search method, themovement direction and the movement amount due to the landinginterference are calculated based on the contact direction and thecontact amount of each dot with the surrounding dot before the dotreplacement and after the dot replacement in a case where at least oneerror of the dot diameter, the dot shape, the dot forming position shiftor the non-jetting is reflected instead of step S741 of FIG. 88.Thereafter, similarly to the flowchart of FIG. 88, the groupclassification process is performed based on the movement direction andthe movement amount before the dot replacement and after the dotreplacement in a case where the error is reflected (step S743), and theevaluation of the dispersibility of each group is performed (step S744).

According to the configuration of the fourteenth embodiment, therespective dot groups in which the influence of the dot movement due tothe landing interference is the same in a case where the predeterminederror which is at least one of the dot diameter, the dot shape, the dotforming position shift or the non-jetting is reflected have favorabledispersibility having, and thus, it is possible to perform the halftonedesign and/or the halftone process in which the image quality isfavorable in a state in which the predetermined error is added or theimage quality deterioration is less (that is, there is the tolerance tothe error) even in a state in which the predetermined error is added.

The group classification and the evaluation of the dispersibility ofeach group may be performed in only a case where the predetermined errorwhich is at least one error of the dot diameter, the dot shape, the dotforming position shift or the non-jetting is reflected, or the groupclassification and the evaluation of the dispersibility of each groupmay be performed in a case where the predetermined error is notreflected and in a case where the predetermined error is reflected.

The processing content performed by the image processing device 20according to the embodiment described in FIGS. 85 to 89 may becomprehended as the image processing method.

Specific Modification Example Described in FIGS. 85 to 89 ModificationExample 18

It has been described in FIGS. 85 to 89 that the movement direction andthe movement amount of the dot movement due to the landing interferenceare calculated based on the information indicating the contact directionand the contact amount of each dot. However, as described in FIG. 73,the movement amount of the dot movement due to the landing interferenceis treated to be approximately proportional to the contact amount of thedot, and thus, it is possible to directly perform the groupclassification process from the contact direction and the contactamount.

In the contact state shown in FIG. 73, it can be seen that even thoughthe movement direction and the movement amount due to the landinginterference are not calculated, since the sum of vectors depicted bytwo illustrated arrows is “0”, the landing interference movement amountis “0”. Even though the calculation of the movement vector described inFIG. 66 is not performed, it is possible to perform the groupclassification process using the vectors indicating the contactdirections and the contact amounts with the surrounding dots.

Accordingly, it is possible to omit the “dot-movement-amount calculationunit 534” described in FIG. 86 or 89.

Modification Example 19

Each of the dispersibility evaluation values of the respective groupsmay be used as the evaluation value for evaluating the influence of thelanding interference, or a weighted sum of the dispersibility evaluationvalues of the respective groups may be used as the evaluation value. Ina case where the predetermined error which is at least one error of thedot diameter, the dot shape, the dot forming position shift or thenon-jetting is reflected, the updating reference of the halftoneparameter or the halftone image may be set using the “evaluation valueon which the error is not reflected” calculated without reflecting thepredetermined error and the “evaluation value on which the error isreflected” calculated by reflecting the predetermined error, or theupdating reference may be set for the weighted sum of the evaluationvalue on which the error is not reflected and the evaluation value onwhich the error is reflected.

Modification Example 20

The updating reference of the halftone parameter of step S505 of FIG. 64or the updating reference of the halftone image of step S524 of FIG. 69or the step S535 of FIG. 71 is not limited to the updating referenceshown in step S716 of FIG. 87 or step S745 of FIG. 88, and variousupdating references may be determined.

For example, the updating reference may be a “case where the imagequality evaluation value or the energy is equal to or less than apredetermined reference value for a determination reference and thedispersibility evaluation value of each group is enhanced” or a “casewhere a weighted sum of the image quality evaluation value or the energyand the dispersibility evaluation value of each group is enhanced”.Instead of the “dispersibility evaluation value of each group”, the“evaluation value generated based on the dispersibility evaluation valueof each group” may be used, and the updating reference may be a “casewhere the image quality evaluation value or the energy is equal to orless than a predetermined reference value for a determination referenceand the evaluation value generated based on the dispersibilityevaluation value of each group is enhanced” or a “case where a weightedsum of the image quality evaluation value or the energy and theevaluation value generated based on the dispersibility evaluation valueof each group is enhanced”. The “energy” mentioned herein corresponds tothe image quality evaluation value of the energy image acquired byapplying the filter such as a Gaussian filter to the dot image.

The “case where the dispersibility evaluation value is enhanced” meansthat an increase/decrease tendency indicating whether the value of thedispersibility evaluation value is increased or decreased iscomprehended, and it is determined that the “dispersibility evaluationvalue is enhanced” in a case where the dispersibility evaluation valueis decreased, that is, in a case where the dispersibility is improved.When it is determined whether or not the dispersibility evaluation valueis enhanced, since it is comprehended whether the dispersibilityevaluation value is increased or decreased by comparing the values ofthe dispersibility evaluation values calculated from different dotimages, a comparison process of comparing the dispersibility evaluationvalue is included. The determining result of whether or not thedispersibility evaluation value is enhanced is based on the “comparingresult” of the comparison process.

The “weighted sum of the image quality evaluation value or the energyand the dispersibility evaluation value” corresponds to one example ofan “evaluation value generated based on the dispersibility evaluationvalue”. The “weighted sum of the image quality evaluation value or theenergy and the dispersibility evaluation value of each group” maycorrespond to one example of a weighted sum of the image qualityevaluation value and the dispersibility evaluation value, or may be aweighted sum of the energy and the dispersibility evaluation value.

Modification Example 21

In a case where the predetermined error (here, the error other than thenon-jetting is used) is reflected on the dot arrangement of the halftoneimage, since the movement direction and the movement amount of the dotgroup on which the error is reflected due to the landing interferenceare greatly changed in most cases unlike the case where the error is notreflected, the group classification process may be performed on only thedot group on which the error is reflected. That is, in the example shownin FIG. 67, the group classification may be performed on only Dot 2 andDot 5 on which the error of the dot forming position shift is reflected.

The dot group as a target on which the group classification process ofevaluating the influence of the dot movement due to the landinginterference is performed is not limited to an aspect in which all thedots included in the dot image are used as targets, and some dots of allthe dots included in the dot image may be used as targets like an aspectin which only the dot group to which the predetermined error is added isused as a target.

Modification Example 22

In a case where the dot forming position shift is reflected as thepredetermined error, since the movement amount due to the landinginterference is greatly changed in a direction parallel to a directionto which the error is added in most cases, the group classificationprocess may be performed for only the dots of which the movementdirection of the dot movement due to the landing interference is adirection parallel to a direction to which the error is added. In thiscase, for only the dots in contact in the direction parallel to thedirection to which the error is added, that is, for only the dotsincluding the dot movement in only the movement direction parallel tothe direction to which the error is added, the group classificationprocess may be performed.

In the example shown in FIG. 67, the dots in contact in the direction towhich the error is added, that is, the dots including the dot movementin only the movement direction parallel to the direction to which theerror is added are Dot 1, Dot 2 and Dot 3. Accordingly, in the exampleshown in FIG. 67, the group classification process is performed on Dot1, Dot 2 and Dot 3.

Modification Example 23

In a case where the dot forming position shift is reflected as thepredetermined error, the dispersibility evaluation value may becalculated for only the group to which the dots of which the movementdirection of the dot movement due to the landing interference is adirection parallel to a direction which the error is added belong.

Modification Example 23 is not limited to the adaptation to thecombination with the configuration of Modification Example 22, and maybe applied to a case where the group classification is performed withoutimposing the restrictions of Modification Example 22 in the groupclassification process. The dispersibility-evaluation-value calculationunit 539 shown in FIG. 86 or 89 may have a function of calculating thedispersibility evaluation value for only the specified group inModification Example 23.

<Variation of System Configuration>

The respective devices such as the means for acquiring thecharacteristic parameters related to the characteristics of the printingsystem, that is, the device that allows the user to input thecharacteristic parameters, the chart output control device that outputsthe characteristic parameter acquisition chart, the printing device thatprints the characteristic parameter acquisition charts according to thecontrol, the device that reads the characteristic parameter acquisitioncharts and acquires the characteristic parameters based on the analyzingresult of the read image, the device that generates two or more kinds ofhalftone processing rules, the chart output control device that outputsthe halftone selection charts, the device that generates the simulationimage from the halftone processing result of the halftone selectionchart, the device that reads the output result of the halftone selectionchart and calculates the image evaluation value from the chart readimage and the device that allows the user to perform the operation ofselecting the halftone processing rule may be an integrated-type system,or may be a functionally-distributed separation type system provided bycombining a plurality of systems.

Similarly, the configurations of the image processing device 20described in FIG. 36, the image processing device 20A described in FIG.37, the image processing device 21 described in FIG. 47, the imageprocessing device 20B described in FIG. 48, the image processing device20 described in FIG. 68, the image processing device 20 described inFIGS. 76 and 82, and the image processing device 20 described in FIGS.86 and 89 may be an integrated-type system, or may be afunctionally-distributed separation type system provided by combining aplurality of systems.

Modification Example 1 of System Configuration

For example, the device that performs the process of acquiring thecharacteristic parameter and the device that performs the process ofgenerating the halftone processing rule may be provided as differentdevices.

Modification Example 2 of System Configuration

The device that performs the process of outputting the halftoneselection chart and the device that allows the user to perform theselection operation of the halftone process may be provided as differentdevices.

Modification Example 3 of System Configuration

The device that performs the process of acquiring the characteristicparameter and the device that retains the priority parameter andperforms the process of generating the halftone processing rule may beprovided as different devices.

Modification Example 4 of System Configuration

As another configuration example, the device that performs the processof outputting the characteristic parameter acquisition chart, the imagereading device that reads the output characteristic parameteracquisition chart, the device that performs the process of generatingand acquiring the characteristic parameter from the read image of thecharacteristic parameter acquisition chart and the device that performsthe process of generating the halftone processing rule using theacquired characteristic parameter may be provided as different devices.

For example, the operation form may be configured such that the processof outputting the characteristic parameter acquisition charts or thehalftone selection charts and reading the images of the charts isperformed in a factory of a printing machine manufacturer or a localprinting system of a printer company, the acquired read images arecollectively sent to a server of the printing machine manufacturer of adevelopment branch or a separate company, the acquisition of thecharacteristic parameters and the generation of the halftone processingrules are performed in a system of the development branch or theseparate company, the generated halftone processing rules are repeatedlysent to the original individual local printing system.

Configuration Examples

The above-described embodiments may have the following configurations.

Configuration Example 1

Whenever a new print job is executed, or during the execution of theprint job, the system error parameter may be automatically acquired fromthe outputting and reading result of the chart, and the halftoneprocessing rule may be generated based on the acquired parameter.Whenever a new print job is executed, or during the execution of theprint job, the chart may be output and read, and the halftone generationmay be newly performed in a case where the system error parameter isequal or greater than a specified reference, or for only the changedparameter. In this case, if the system error parameter (including thecharacteristic parameter) is not changed, that is, in a case where thechange amount of the system error parameter falls in a specifiedreference, the process of generating the halftone processing rule isomitted, and a time loss is not generated.

The chart may be output together with an image immediately before theimage on which the halftone process is performed. In this case, the timeloss is reduced. The halftone process and the process of generating thehalftone processing rule may be performed in parallel.

Configuration Example 2

Any one of the chart content, the chart output condition, the scanningcondition (synonym for the reading condition of the chart), theparameter acquisition method and the generation content of the halftoneprocessing rule, or a plurality of combinations thereof may be changedin response to the quality request of the user for the print imageacquired by the quality request acquisition means. In such aconfiguration, it is possible to reduce a time loss required for theprocess.

Configuration 3

A dedicated chart (dot-reproduction-accuracy investigation dedicatedchart) to investigate dot reproduction accuracy may be output by thedot-reproduction-accuracy-investigation-dedicated-chart output means,the dot reproduction accuracy may be analyzed from thedot-reproduction-accuracy investigation dedicated chart by thedot-reproduction-accuracy analysis means, and any one of the content ofthe parameter acquisition chart, the chart output condition, thescanning condition, the parameter acquisition method and the generationcontent of the halftone processing rule or a plurality of combinationsthereof may be changed based on the analyzing result. In such aconfiguration, it is possible to reduce a time loss required for theprocess.

<Program Causing Computer to Function as Image Processing Device>

As the image processing device described in the above-describedembodiments, programs for operating a computer may be recorded a compactdisc read-only memory (CD-ROM), a magnetic disk, and a computer-readablemedium (non-transitory tangible information storage medium), and theprograms may be provided through the information storage medium. Insteadof the aspect in which the programs are provided while being stored inthe information storage medium, program signals may be provided as adownload service via a communication network such as the Internet.

The programs are incorporated in the computer, and thus, the computermay realize the function of the image processing device 20. A part orall of the programs for realizing printing control including the imageprocessing function described in the present embodiment may beincorporated in a higher control device such as a host computer, or maybe operated as an operating program of a central processing unit (CPU)of the printing device 24.

<<Printing Medium>>

The “printing medium” is referred to as various terms such as a printmedium, a printed medium, an image forming target medium, an imagereceiving medium, a jetted medium, and a recording sheet. When thepresent invention is implemented, the material or shape of the printingmedium is not particularly limited, and various sheets such as resinsheet such as continuous paper, cut paper, seal paper or overheadprojector (OHP) sheet, film, fabric, nonwoven fabric, a printed board onwhich a wiring pattern is formed, and rubber sheet may be usedirrespective of the material or shape thereof.

<<Image Quality Deterioration>>

The “image quality deterioration” mentioned in the present specificationprimarily refers to the occurrence of the streak or unevenness andgranularity deterioration. As the image quality deterioration, there arevarious causes such as ink aggregate unevenness, gloss unevenness,banding of density, color, gloss, or a combination thereof, or bleeding.

<<Combination of Embodiments>>

The configuration acquired by appropriately combining the configurationsdescribed as the aforementioned embodiments or modification examples orthe other configuration examples may be adopted. For example, theconfiguration of the following combination may be adopted.

[1] The configurations of the first embodiment to the third embodimentmay be appropriately combined with the configuration of the fourthembodiment or the configuration of the modification example of thefourth embodiment.

[2] The configurations of two or more embodiments of the firstembodiment, the second embodiment and the third embodiment may beappropriately combined with the configuration of the seventh embodiment.

[3] The configuration of the ninth embodiment or the configurations ofthe first embodiment to the third embodiment may be appropriatelycombined with the configuration of the eighth embodiment.

[4] The configurations of two or more modification examples ofModification Example 5, Modification Example 6 and Modification Example7 may be appropriately combined with the configuration of the tenthembodiment.

[5] The configurations of two or more modification examples ofModification Example 10, Modification Example 11 and ModificationExample 12 may be appropriately combined with the configuration of theeleventh embodiment.

[6] The configurations of two or more modification examples ofModification Example 15, Modification Example 16 and ModificationExample 17 may be appropriately combined with the configuration of thetwelfth embodiment.

[7] The configurations of two or more modification examples ofModification Example 21, Modification Example 22 and ModificationExample 23 may be appropriately combined with the configuration of thethirteenth embodiment or the configuration of the fourteenth embodiment.

Advantages of Embodiments

According to the aforementioned embodiments, there are the followingadvantages.

(1) It is possible to simply acquire various characteristic parametersrelated to the characteristics of the printing system from the readimage of the characteristic parameter acquisition chart. Accordingly, itis possible to greatly reduce the operation load of the user related tothe setting of the characteristic parameters unlike the configuration inwhich the user inputs all the various characteristic parameters throughthe user interface. It is possible to generate the halftone processingrule appropriate for the printing system based on the characteristicparameters acquired from the characteristic parameter acquisition chart.

(2) It is possible to generate the halftone processing rule appropriatefor the printing system in consideration of the system error on theassumption of the actual printing performed by the printing system.Accordingly, it is possible to realize the appropriate halftone processcapable of acquiring favorable image quality, and it is possible toacquire the print image having favorable image quality.

(3) Since the characteristic parameters are updated depending on thedifference between the existing characteristic parameter and the newcharacteristic parameter, it is possible to update the characteristicparameter according to the change of the characteristics of the printingsystem. Accordingly, the halftone processing rule is generated using theupdated characteristic parameter, and thus, it is possible to performthe printing using the halftone processing rule corresponding to thechange of the characteristics of the printing system.

(4) According to the method of generating the processing rule, duringthe execution of an arbitrary print job, the characteristic parameteracquisition chart used to generate the halftone processing rule used forthe subsequently output image is output together with the image, andthus, it is possible to determine the change of the characteristics ofthe printing system whenever the image is output (whenever thecharacteristic parameter acquisition chart is output) and it is possibleto generate the halftone processing rule corresponding to the change ofthe characteristics of the printing system. Accordingly, the image isoutput using the halftone processing rule corresponding to the change ofthe characteristics of the printing system, and thus, it is possible toprevent the image quality from being deteriorated even in a case wherethe characteristics of the printing system are changed.

(5) As described in the seventh embodiment, the chart output conditionis set depending on the printing mode, and thus, it is possible toappropriately comprehend the characteristic parameters indicating thecharacteristics of the printing system for each printing mode.

(6) Since the characteristic parameter acquisition chart is optimized bysetting the chart output condition depending on the printing mode, theprocessing time until the characteristic parameter is acquired after thecharacteristic parameter acquisition chart is output is reduced in acase where the characteristic parameter acquisition chart is reduced.

(7) Since the characteristic parameter acquisition chart is optimized bysetting the chart output condition depending on the printing mode, theusage amount of the ink and the usage amount of the printing medium useduntil the characteristic parameter is acquired after the characteristicparameter acquisition chart is output in a case where the characteristicparameter acquisition chart is reduced.

(8) As described in the eighth embodiment to the fourteenth embodiment,it is possible to generate the halftone parameter or the halftone imagehaving tolerance to the landing interference. It is possible to suppressthe image quality deterioration caused by the landing interference, andit is possible to realize the generation of the halftone image capableof forming the image having high image quality.

It is possible to generate the halftone parameter or the halftone imagehaving tolerance to at least one error of the dot diameter, the dotshape, the dot forming position shift or the non-jetting, and it ispossible to suppress the image quality deterioration caused by theerror.

(9) It is possible to generate the halftone processing rule appropriatefor the printing system in consideration of the system error on theassumption of the actual printing performed by the printing system.Accordingly, it is possible to realize the appropriate halftone processcapable of acquiring favorable image quality, and it is possible toacquire the print image having favorable image quality.

(10) It is possible to simply acquire various characteristic parametersrelated to the characteristics of the printing system from the readimage of the characteristic parameter acquisition chart. Accordingly, itis possible to greatly reduce the operation load of the user related tothe setting of the characteristic parameters unlike the configuration inwhich the user inputs all the various characteristic parameters throughthe user interface. It is possible to generate the halftone processingrule appropriate for the printing system based on the characteristicparameters acquired from the characteristic parameter acquisition chart.

The constituent requirements of the above-described embodiments of thepresent invention may be changed, added and removed without departingfrom the gist of the present invention. The present invention is notlimited to the above-described embodiment, and may be variously modifiedby those skilled in the art within the technical spirit of the presentinvention.

EXPLANATION OF REFERENCES

-   -   10: printing system    -   20, 20A, 21: image processing device    -   24: printing device    -   26: image reading device    -   32: display device    -   34: input device    -   52: characteristic parameter acquisition unit    -   53: system-error-parameter acquisition unit    -   54: characteristic parameter storage unit    -   55: system-error-parameter storage unit    -   56: priority parameter retention unit    -   58: halftone process generation unit    -   58A: previous-stage halftone process generation unit    -   58B; halftone automatic selection unit    -   59: determination-evaluation-value calculation unit    -   60: halftone-processing-rule storage unit    -   62: characteristic-parameter-acquisition-chart generation unit    -   64: image analysis unit    -   67: system error setting unit    -   70: evaluation value calculation unit    -   74: image quality evaluation processing unit    -   76: halftone-selection-chart generation unit    -   100: characteristic parameter acquisition chart    -   101: printing medium    -   102C, 102M, 102Y, 102K: single dot pattern    -   104C, 104M, 104Y, 104K: first continuous dot pattern    -   106C, 106M, 106Y, 106K: second continuous dot pattern    -   150: halftone selection chart    -   151, 152: primary color patch    -   200: characteristic parameter acquisition chart    -   201: printing medium    -   202C, 202M, 202Y, 202K: single dot pattern    -   204C, 204M, 204Y, 204K: first continuous dot pattern    -   206C, 206M, 206Y, 206K: second continuous dot pattern    -   230: characteristic parameter update determination unit    -   300: printing mode selection unit    -   302: chart-output-condition setting unit    -   304: characteristic-parameter-acquisition-chart storage unit    -   323: specified value acquisition unit    -   532: halftone image analysis unit    -   532A: first halftone image analysis unit    -   532B: second halftone image analysis unit    -   534: dot-movement-amount calculation unit    -   534A: first dot-movement-amount calculation unit    -   534B: second dot-movement-amount calculation unit    -   535: movement-amount-change calculation unit    -   536: landing-interference-influence evaluation unit    -   537: group classification processing unit    -   538: reference value storage unit    -   539: dispersibility-evaluation-value calculation unit    -   546: error reflection processing unit    -   558: contact-state-change calculation unit

What is claimed is:
 1. A printing system comprising: a processor; and amemory, the memory storing instructions to cause the processor toperform outputting a characteristic parameter acquisition chartincluding a pattern for acquiring characteristic parameters related tocharacteristics of a printing system; reading the characteristicparameter acquisition chart output by the outputting; acquiring thecharacteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart acquired by the reading;generating halftone processing rules that define processing contents ofhalftone processes used in the printing system based on thecharacteristic parameters acquired by the characteristic parameteracquisition; and forming dots on a printing medium via a plurality ofprinting elements, wherein the characteristics of the printing systemare characteristics that include at least one of: individual recordingcharacteristics of the printing elements; and common characteristics tothe printing elements, wherein the acquiring acquires parameters relatedto the individual recording characteristics of the printing elements andthe common characteristics to the printing elements from the read imageof the characteristic parameter acquisition chart on which recording hasbeen performed multiple times by using same printing elements by theoutputting, wherein the acquiring acquires parameters related tocharacteristic errors of the printing system from an average value ofmeasurement values obtained from the read image, the characteristicerrors being errors that have reproducibility, and wherein the acquiringacquires parameters related to random system errors of the printingsystem from a variation in the average value of the measurement valuesobtained from the read image, the random system errors being errors thatare irregularly changed.
 2. The printing system according to claim 1,wherein the recording characteristics comprise characteristics thatinclude at least one of a dot density, a dot diameter, a dot shape, adot recording position error, or recording inexecutable abnormality. 3.The printing system according to claim 1, wherein the commoncharacteristics comprise characteristics that include at least one of anaverage dot density, an average dot diameter, an average dot shape, orlanding interference.
 4. The printing system according to claim 1,wherein the characteristic parameter acquisition chart includes acontinuous dot pattern in which two or more dots are recorded so as tobe in contact, and wherein the acquiring acquires a parameter related tothe landing interference from the continuous dot pattern.
 5. Theprinting system according to claim 4, wherein the characteristicparameter acquisition chart includes multiple kinds of continuous dotpatterns in which at least any one of an inter-dot distance between thetwo or more dots or a recording time difference between the two or moredots is differentiated.
 6. The printing system according to claim 1,wherein the characteristic parameter acquisition chart includes adiscrete dot pattern in which dots are discretely recorded in anisolation state in which a single dot is isolated from another dot, andwherein the acquiring generates dispersion information related todispersion of dots from the discrete dot pattern.
 7. A method ofgenerating a halftone processing rule, comprising: outputting acharacteristic parameter acquisition chart including a pattern foracquiring characteristic parameters related to characteristics of aprinting system; reading the characteristic parameter acquisition chartoutput by the outputting; acquiring the characteristic parameters byanalyzing a read image of the characteristic parameter acquisition chartacquired by the reading; generating halftone processing rules thatdefine processing contents of halftone processes used in the printingsystem based on the characteristic parameters acquired by thecharacteristic parameter acquisition; and forming dots on a printingmedium via a plurality of printing elements, wherein the characteristicsof the printing system are characteristics that include at least one of:individual recording characteristics of the printing elements; andcommon characteristics to the printing elements, wherein the acquiringacquires parameters related to the individual recording characteristicsof the printing elements and the common characteristics to the printingelements from the red image of the characteristic parameter acquisitionchart on which recording has been performed multiple times by using sameprinting elements by the outputting, wherein the acquiring acquiresparameters related to characteristic errors of the printing system froman average value of measurement values obtained from the read image, thecharacteristic errors being errors that have reproducibility, andwherein the acquiring acquires parameters related to random systemerrors of the printing system from a variation in the average value ofthe measurement values obtained from the read image, the random systemerrors being errors that are irregularly changed.
 8. An image processingdevice comprising: a processor; and a memory, the memory storinginstructions to cause the processor to perform outputting acharacteristic parameter acquisition chart including a pattern foracquiring characteristic parameters related to characteristics of aprinting system; reading the characteristic parameter acquisition chartoutput by the outputting; acquiring the characteristic parameters byanalyzing a read image of the characteristic parameter acquisition chartacquired by the reading; generating halftone processing rules thatdefine processing contents of halftone processes used in the printingsystem based on the characteristic parameters acquired by thecharacteristic parameter acquisition; and forming dots on a printingmedium via a plurality of printing elements, wherein the characteristicsof the printing system are characteristics that include at least one of:individual recording characteristics of the printing elements; andcommon characteristics to the printing elements, wherein the acquiringacquires parameters related to the individual recording characteristicsof the printing elements and the common characteristics to the printingelements from the read image of the characteristic parameter acquisitionchart on which recording has been performed multiple times by using sameprinting elements by the outputting, wherein the acquiring acquiresparameters related to characteristic errors of the printing system froman average value of measurement values obtained from the read image, thecharacteristic errors being errors that have reproducibility, andwherein the acquiring acquires parameters related to random systemerrors of the printing system from a variation in the average value ofthe measurement values obtained from the read image, the random systemerrors being errors that are irregularly changed.
 9. A non-transitoryand tangible computer-readable recording medium which stores a program,such that when the program is read and executed by the computer, thecomputer performs: outputting a characteristic parameter acquisitionchart including a pattern for acquiring characteristic parametersrelated to characteristics of a printing system; reading thecharacteristic parameter acquisition chart output by the outputting;acquiring the characteristic parameters by analyzing a read image of thecharacteristic parameter acquisition chart acquired by the reading;generating halftone processing rules that define processing contents ofhalftone processes used in the printing system based on thecharacteristic parameters acquired by the characteristic parameteracquisition; and forming dots on a printing medium via a plurality ofprinting elements, wherein the characteristics of the printing systemare characteristics that include at least one of: individual recordingcharacteristics of the printing elements; and common characteristics tothe printing elements, wherein the acquiring acquires parameters relatedto the individual recording characteristics of the printing elements andthe common characteristics to the printing elements from the read imageof the characteristic parameter acquisition chart on which recording hasbeen performed multiple times by using same printing elements by theoutputting, wherein the acquiring acquires parameters related tocharacteristic errors of the printing system from an average value ofmeasurement values obtained from the read image, the characteristicerrors being errors that have reproducibly, and wherein the acquiringacquires parameters related to random system errors of the printingsystem from a variation in the average value of the measurement valuesobtained from the read image, the random system errors being errors thatare irregularly changed.